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Tomatoes and Marigolds (companion planting)

Tomatoes and Marigolds (companion planting)

Companion or granchild reading to senior or grandfather

Companion or granchild reading to senior or grandfather

Mentally disabled woman with a second woman and a companion dog

Mentally disabled woman with a second woman and a companion dog

Parsley herb and spring onions growing in a companion planting permaculture garden bed in a home hobby garden, next to red Swiss

Parsley herb and spring onions growing in a companion planting permaculture garden bed in a home hobby garden, next to red Swiss

close-up of companion planting in a garden bed

close-up of companion planting in a garden bed

Growing green pea and green onions at the same place

Growing green pea and green onions at the same place

Senior adult woman being introduced to tablet with volunteer assistance

Senior adult woman being introduced to tablet with volunteer assistance

Companion

Companion

Dog companion T-shirt graphics.

Dog companion T-shirt graphics.

Dog companion T-shirt graphics.

Dog companion T-shirt graphics.

Dog companion T-shirt graphics.

Dog companion T-shirt graphics.

Intricate Line Art of Lord Ganesha with His Mouse Companion - Hindu Deity Illustration

Intricate Line Art of Lord Ganesha with His Mouse Companion - Hindu Deity Illustration

Companion robot evolution timeline infographics

Companion robot evolution timeline infographics

Farm and Companion Animals for Coloring

Farm and Companion Animals for Coloring

Old grumpy and lonely brown pud or bulldog sitting in front of the window waiting his owner from the work

Old grumpy and lonely brown pud or bulldog sitting in front of the window waiting his owner to come back from the work, pet, cute, canine, puppy, animal, breed, white, fur, domestic, funny, doggy, face, friend, purebred, adorable, head, happy, mammal, looking, young, animals, portrait, stare, serious, furry, mutt, wet, outdoors, sad, tired, down, lying, frown, pug, adult, beagle, stubborn, beast, brute, challenge, strong, best, companion. Old grumpy and lonely brown pud or bulldog sitting in front of the window waiting his owner to come back from the work, pet, cute, canine, puppy, animal, breed, white, fur, domestic, funny, doggy, face, friend, purebred, adorable, head, happy, mammal, looking, young, animals, portrait, stare, serious, furry, mutt, wet, outdoors, sad, tired, down, lying, frown, pug, adult, beagle, stubborn, beast, brute, challenge, strong, best, companion

Borzoi the large-scale dog Russia companion dog gentleman peaceful big slender runs the calm dignified white to run friendly plays the snowy mountain South Pole stone to snow in the winter the back battle yellow

Borzoi front the large-scale dog Russia companion dog gentleman peaceful big slender runs the calm dignified white to play friendly the snowy mountain South Pole stone to snow stands in the winter half-length excited

Borzoi the large-scale dog Russia companion dog gentleman peaceful big slender runs calm dignified white two to create a disturbance friendly runs snows the snowy mountain stone

Burnet Companion moth in the high grass.

It see companion of it in play. It see companion of it in play.

The dachshund see companion in play with.

Chihuahua FAMILY COMPANION FOR ELDERS

Chihuahua FAMILY COMPANION FOR ELDERS

The cat is seeing its companion playing. The cat is seeing its companion playing.

A leopard cat is seeing its companion playing. A leopard cat is seeing its companion playing.

The lazy housecat, pet and companion. A portrait of...

The lazy housecat, pet and companion. A portrait of...

The angry housecat, pet and companion. A portrait of...

Curious housecat

The curious housecat, pet and companion. A portrait of...

A German Shepherd Farm Dog

The German Shepherd Dog is a large-sized breed belonging to the herding group of working dogs. Intelligent as it is versatile, this breed was originally developed in Germany to guard and herd a shepherd`s flocks. The German Shepherd requires an active lifestyle, and makes for an ideal companion and protector. The German Shepherd Dog is a large-sized breed belonging to the herding group of working dogs. Intelligent as it is versatile, this breed was originally developed in Germany to guard and herd a shepherd`s flocks. The German Shepherd requires an active lifestyle, and makes for an ideal companion and protector.

My gear and traveling companion. My gear and traveling companion

BRUSSELS GRIFFON

Small dog Growth: 18 - 20 cm Weight: 2,5 - 5,5 kg Brussels Griffon largely a wonderful companion.

Labrador Retriever

My companion!!! Labrador Retriever. How can you possibly resist his puppy dog eyes??

Dog in a tractor (Spaniel&#x29

An agricultural workers faithful companion, happy to spend hours ploughing fields with her master, in a tractor cab. An agricultural workers faithful companion, happy to spend hours ploughing fields with her master, in a tractor cab.

Freshness organic green peppers and basil herb

Freshness, healthy lifestyle diet, organic green pepper capsicum and basil herb companion plants. Freshness, healthy lifestyle diet, organic green pepper capsicum and basil herb companion plants

Companion Care Restroom

A sign indicating a coed style restroom. A sign indicating a coed style restroom.

Portrait of Birch in russian hat

Portrait of best friend and companion (our son in truth) posing in his russian fur hat. Portrait of best friend and companion (our son in truth) posing in his russian fur hat

Dog, Dog Breed, Carnivore, Companion Dog

Dog, Dog breed, Carnivore, Companion dog, Fawn, Terrestrial animal

Dog, Dog Breed, Carnivore, Companion Dog

Dog, Dog breed, Carnivore, Companion dog, Fawn, Terrestrial animal

Dog, Dog Breed, Carnivore, Companion Dog

Dog, Dog breed, Carnivore, Companion dog, Working animal, Terrier

Herbaceous dicot vine: Cucurbita

long section: Cucurbita stem magnification: 100x Phloem consists of large clear sieve tubes with pitted cell walls and sieve plates and small narrow green stained companion cells. Many sieve plates have deposits of a mucoid p-protein that forms as part of the trauma response in injured phloem. Between the xylem and phloem are a few regularly arranged layers of elongated cambium cells. long section: Cucurbita stem magnification: 100x Phloem consists of large clear sieve tubes with pitted cell walls and sieve plates and small narrow green stained companion cells. Many sieve plates have deposits of a mucoid p-protein that forms as part of the trauma response in injured phloem. Between the xylem and phloem are a few regularly arranged layers of elongated cambium cells.

Herbaceous dicot vine: Cucurbita

long section: Cucurbita stem magnification: 100x Bicollateral vascular bundles have two zones of phloem and two zones of cambium on either side of the central xylem with outer facing tissues more heavily developed. The sequence of tissues in the bicollateral vascular bundle is outer phloem, outer cambium, xylem, inner cambium and inner phloem with outer more heavily developed. Walls of xylem vessels have lignin free pits and lignin thickenings that form rings, spirals, networks and solid blocks. Phloem consists of large clear sieve tubes with pitted cell walls and sieve plates and small narrow green stained companion cells. Many sieve plates have deposits of a mucoid p-protein that forms as part of the trauma response in injured phloem. Between the xylem and phloem are a few regularly arranged layers of elongated cambium cells. long section: Cucurbita stem magnification: 100x Bicollateral vascular bundles have two zones of phloem and two zones of cambium on either side of the central xylem with outer facing tissues more heavily developed. The sequence of tissues in the bicollateral vascular bundle is outer phloem, outer cambium, xylem, inner cambium and inner phloem with outer more heavily developed. Walls of xylem vessels have lignin free pits and lignin thickenings that form rings, spirals, networks and solid blocks. Phloem consists of large clear sieve tubes with pitted cell walls and sieve plates and small narrow green stained companion cells. Many sieve plates have deposits of a mucoid p-protein that forms as part of the trauma response in injured phloem. Between the xylem and phloem are a few regularly arranged layers of elongated cambium cells.

Herbaceous dicot vine: Cucurbita

long section: Cucurbita stem magnification: 100x The epidermis is usually single layered with an outer cuticle and multicellular trichomes. The cortex consists of a conspicuous hypodermis of parenchyma cells with collections of collenchyma cells at the stem ridges. The deepest layer of the cortex is marked by a starch sheath (large barrel-shaped cells contain starch granules). Bicollateral vascular bundles have two zones of phloem and two zones of cambium on either side of the central xylem with outer facing tissues more heavily developed. The sequence of tissues in the bicollateral vascular bundle is outer phloem, outer cambium, xylem, inner cambium and inner phloem with outer more heavily developed. Walls of xylem vessels have lignin free pits and lignin thickenings that form rings, spirals, networks and solid blocks. Phloem consists of large clear sieve tubes with pitted cell walls and sieve plates and small narrow green stained companion cells. Many sieve plates have deposits of a mucoid p-protein that forms as part of the trauma response in injured phloem. Between the xylem and phloem are a few regularly arranged layers of elongated cambium cells. long section: Cucurbita stem magnification: 100x The epidermis is usually single layered with an outer cuticle and multicellular trichomes. The cortex consists of a conspicuous hypodermis of parenchyma cells with collections of collenchyma cells at the stem ridges. The deepest layer of the cortex is marked by a starch sheath (large barrel-shaped cells contain starch granules). Bicollateral vascular bundles have two zones of phloem and two zones of cambium on either side of the central xylem with outer facing tissues more heavily developed. The sequence of tissues in the bicollateral vascular bundle is outer phloem, outer cambium, xylem, inner cambium and inner phloem with outer more heavily developed. Walls of xylem vessels have lignin free pits and lignin thickenings that form rings, spirals, networks and solid blocks. Phloem consists of large clear sieve tubes with pitted cell walls and sieve plates and small narrow green stained companion cells. Many sieve plates have deposits of a mucoid p-protein that forms as part of the trauma response in injured phloem. Between the xylem and phloem are a few regularly arranged layers of elongated cambium cells.

Herbaceous dicot vine: Cucurbita

long section: Cucurbita stem magnification: 40x The epidermis is usually single layered with an outer cuticle and multicellular trichomes. The cortex consists of a conspicuous hypodermis of parenchyma cells with collections of collenchyma cells at the stem ridges. The deepest layer of the cortex is marked by a starch sheath (large barrel-shaped cells contain starch granules). Bicollateral vascular bundles have two zones of phloem and two zones of cambium on either side of the central xylem with outer facing tissues more heavily developed. The sequence of tissues in the bicollateral vascular bundle is outer phloem, outer cambium, xylem, inner cambium and inner phloem with outer more heavily developed. Walls of xylem vessels have lignin free pits and lignin thickenings that form rings, spirals, networks and solid blocks. Phloem consists of large clear sieve tubes with pitted cell walls and sieve plates and small narrow green stained companion cells. Many sieve plates have deposits of a mucoid p-protein that forms as part of the trauma response in injured phloem. Between the xylem and phloem are a few regularly arranged layers of elongated cambium cells. long section: Cucurbita stem magnification: 40x The epidermis is usually single layered with an outer cuticle and multicellular trichomes. The cortex consists of a conspicuous hypodermis of parenchyma cells with collections of collenchyma cells at the stem ridges. The deepest layer of the cortex is marked by a starch sheath (large barrel-shaped cells contain starch granules). Bicollateral vascular bundles have two zones of phloem and two zones of cambium on either side of the central xylem with outer facing tissues more heavily developed. The sequence of tissues in the bicollateral vascular bundle is outer phloem, outer cambium, xylem, inner cambium and inner phloem with outer more heavily developed. Walls of xylem vessels have lignin free pits and lignin thickenings that form rings, spirals, networks and solid blocks. Phloem consists of large clear sieve tubes with pitted cell walls and sieve plates and small narrow green stained companion cells. Many sieve plates have deposits of a mucoid p-protein that forms as part of the trauma response in injured phloem. Between the xylem and phloem are a few regularly arranged layers of elongated cambium cells.

Herbaceous dicot vine: Cucurbita

long section: Cucurbita stem magnification: 40x Bicollateral vascular bundles have two zones of phloem and two zones of cambium on either side of the central xylem with outer facing tissues more heavily developed. The sequence of tissues in the bicollateral vascular bundle is outer phloem, outer cambium, xylem, inner cambium and inner phloem with outer more heavily developed. Walls of xylem vessels have lignin free pits and lignin thickenings that form rings, spirals, networks and solid blocks. Phloem consists of large clear sieve tubes with pitted cell walls and sieve plates and small narrow green stained companion cells. Many sieve plates have deposits of a mucoid p-protein that forms as part of the trauma response in injured phloem. Between the xylem and phloem are a few regularly arranged layers of elongated cambium cells. long section: Cucurbita stem magnification: 40x Bicollateral vascular bundles have two zones of phloem and two zones of cambium on either side of the central xylem with outer facing tissues more heavily developed. The sequence of tissues in the bicollateral vascular bundle is outer phloem, outer cambium, xylem, inner cambium and inner phloem with outer more heavily developed. Walls of xylem vessels have lignin free pits and lignin thickenings that form rings, spirals, networks and solid blocks. Phloem consists of large clear sieve tubes with pitted cell walls and sieve plates and small narrow green stained companion cells. Many sieve plates have deposits of a mucoid p-protein that forms as part of the trauma response in injured phloem. Between the xylem and phloem are a few regularly arranged layers of elongated cambium cells.

Herbaceous dicot vine: P-protein plugs in phloem Cucurbita

long section: Cucurbita stem magnification: 400x The epidermis is usually single layered with an outer cuticle and multicellular trichomes. Phloem consists of large clear sieve tubes with pitted cell walls and sieve plates and small narrow green stained companion cells. Many sieve plates have deposits of a mucoid p-protein that forms as part of the trauma response in injured phloem. Between the xylem and phloem are a few regularly arranged layers of elongated cambium cells. long section: Cucurbita stem magnification: 400x The epidermis is usually single layered with an outer cuticle and multicellular trichomes. Phloem consists of large clear sieve tubes with pitted cell walls and sieve plates and small narrow green stained companion cells. Many sieve plates have deposits of a mucoid p-protein that forms as part of the trauma response in injured phloem. Between the xylem and phloem are a few regularly arranged layers of elongated cambium cells.

Herbaceous dicot vine: Xylem vessels in Cucurbita

long section: Cucurbita stem magnification: 400x Bicollateral vascular bundles have two zones of phloem and two zones of cambium on either side of the central xylem with outer facing tissues more heavily developed. Walls of xylem vessels have lignin free pits and lignin thickenings that form rings, spirals, networks and solid blocks. Phloem consists of large clear sieve tubes with pitted cell walls and sieve plates and small narrow green stained companion cells. Many sieve plates have deposits of a mucoid p-protein that forms as part of the trauma response in injured phloem. Between the xylem and phloem are a few regularly arranged layers of elongated cambium cells. long section: Cucurbita stem magnification: 400x Bicollateral vascular bundles have two zones of phloem and two zones of cambium on either side of the central xylem with outer facing tissues more heavily developed. Walls of xylem vessels have lignin free pits and lignin thickenings that form rings, spirals, networks and solid blocks. Phloem consists of large clear sieve tubes with pitted cell walls and sieve plates and small narrow green stained companion cells. Many sieve plates have deposits of a mucoid p-protein that forms as part of the trauma response in injured phloem. Between the xylem and phloem are a few regularly arranged layers of elongated cambium cells.

Herbaceous dicot vine: Xylem vessels in Cucurbita

long section: Cucurbita stem magnification: 400x Bicollateral vascular bundles have two zones of phloem and two zones of cambium on either side of the central xylem with outer facing tissues more heavily developed. Walls of xylem vessels have lignin free pits and lignin thickenings that form rings, spirals, networks and solid blocks. Phloem consists of large clear sieve tubes with pitted cell walls and sieve plates and small narrow green stained companion cells. Many sieve plates have deposits of a mucoid p-protein that forms as part of the trauma response in injured phloem. Between the xylem and phloem are a few regularly arranged layers of elongated cambium cells. long section: Cucurbita stem magnification: 400x Bicollateral vascular bundles have two zones of phloem and two zones of cambium on either side of the central xylem with outer facing tissues more heavily developed. Walls of xylem vessels have lignin free pits and lignin thickenings that form rings, spirals, networks and solid blocks. Phloem consists of large clear sieve tubes with pitted cell walls and sieve plates and small narrow green stained companion cells. Many sieve plates have deposits of a mucoid p-protein that forms as part of the trauma response in injured phloem. Between the xylem and phloem are a few regularly arranged layers of elongated cambium cells.

Herbaceous dicot vine: Cucurbita

long section: Cucurbita stem magnification: 40x The epidermis is usually single layered with an outer cuticle and multicellular trichomes. The cortex consists of a conspicuous hypodermis of parenchyma cells with collections of collenchyma cells at the stem ridges. The deepest layer of the cortex is marked by a starch sheath (large barrel-shaped cells contain starch granules). Bicollateral vascular bundles have two zones of phloem and two zones of cambium on either side of the central xylem with outer facing tissues more heavily developed. The sequence of tissues in the bicollateral vascular bundle is outer phloem, outer cambium, xylem, inner cambium and inner phloem with outer more heavily developed. Walls of xylem vessels have lignin free pits and lignin thickenings that form rings, spirals, networks and solid blocks. Phloem consists of large clear sieve tubes with pitted cell walls and sieve plates and small narrow green stained companion cells. Many sieve plates have deposits of a mucoid p-protein that forms as part of the trauma response in injured phloem. Between the xylem and phloem are a few regularly arranged layers of elongated cambium cells. long section: Cucurbita stem magnification: 40x The epidermis is usually single layered with an outer cuticle and multicellular trichomes. The cortex consists of a conspicuous hypodermis of parenchyma cells with collections of collenchyma cells at the stem ridges. The deepest layer of the cortex is marked by a starch sheath (large barrel-shaped cells contain starch granules). Bicollateral vascular bundles have two zones of phloem and two zones of cambium on either side of the central xylem with outer facing tissues more heavily developed. The sequence of tissues in the bicollateral vascular bundle is outer phloem, outer cambium, xylem, inner cambium and inner phloem with outer more heavily developed. Walls of xylem vessels have lignin free pits and lignin thickenings that form rings, spirals, networks and solid blocks. Phloem consists of large clear sieve tubes with pitted cell walls and sieve plates and small narrow green stained companion cells. Many sieve plates have deposits of a mucoid p-protein that forms as part of the trauma response in injured phloem. Between the xylem and phloem are a few regularly arranged layers of elongated cambium cells.

Gymnosperm Stem: Two Year Pinus

cross section: Pinus stem magnification: 100x During the first year of growth the cutinized epidermis is replaced by protective growth of cork rich periderm. The outer periderm consists of layers of cork cells, the phellem, which produces waterproofing suberin. Cork cells are dead at maturity. Deep to the phellem is a living layer of cork cambium or phellogen and beneath that, layers of cork parenchyma or phelloderm. Many cells in the periderm contain dark staining tannins. The cortex is divided into a thin outer hypodermis of lignified sclerenchyma cells and thicker inner cortex of thin walled parenchyma cells containing chloroplasts. Large resin ducts are surrounded by secretory parenchyma that produces resins and turpentines. Some cells enlarge into dark staining tyloses. Both endoderm and pericycle are inconspicuous. The vascular cylinder or stele in young stems consists of a ring of vascular bundles interspaced with medullary rays of parenchyma cells. Seasonal activity of the cambium replaces the isolated vascular bundles with well-defined annual rings of secondary phloem and xylem. Xylem is endarch with protoxylem found towards center of the stem and younger metaxylem towards the periphery of the stem. Protoxylem consists of annular and spiral tracheids with only tracheids found in metaxylem. True xylem vessels are lacking. Because of the greater production of xylem, the vascular cylinder is dominated by radially arranged rays of secondary xylem interspaced with medullary rays of parenchyma cells. Conspicuous resin ducts are present throughout the xylem. Phloem is endarch but annual growth the of stem makes it difficult to distinguish between older protophloem to the periphery and younger metapholem towards center of the stem. Phloem lacks companion cells, consisting entirely of sieve tubes and phloem parenchyma. Medullary rays in the secondary phloem include protein rich albuminous cells. A well-defined pith of parenchyma cells is interrupted by a few large resin ducts. cross section: Pinus stem magnification: 100x During the first year of growth the cutinized epidermis is replaced by protective growth of cork rich periderm. The outer periderm consists of layers of cork cells, the phellem, which produces waterproofing suberin. Cork cells are dead at maturity. Deep to the phellem is a living layer of cork cambium or phellogen and beneath that, layers of cork parenchyma or phelloderm. Many cells in the periderm contain dark staining tannins. The cortex is divided into a thin outer hypodermis of lignified sclerenchyma cells and thicker inner cortex of thin walled parenchyma cells containing chloroplasts. Large resin ducts are surrounded by secretory parenchyma that produces resins and turpentines. Some cells enlarge into dark staining tyloses. Both endoderm and pericycle are inconspicuous. The vascular cylinder or stele in young stems consists of a ring of vascular bundles interspaced with medullary rays of parenchyma cells. Seasonal activity of the cambium replaces the isolated vascular bundles with well-defined annual rings of secondary phloem and xylem. Xylem is endarch with protoxylem found towards center of the stem and younger metaxylem towards the periphery of the stem. Protoxylem consists of annular and spiral tracheids with only tracheids found in metaxylem. True xylem vessels are lacking. Because of the greater production of xylem, the vascular cylinder is dominated by radially arranged rays of secondary xylem interspaced with medullary rays of parenchyma cells. Conspicuous resin ducts are present throughout the xylem. Phloem is endarch but annual growth the of stem makes it difficult to distinguish between older protophloem to the periphery and younger metapholem towards center of the stem. Phloem lacks companion cells, consisting entirely of sieve tubes and phloem parenchyma. Medullary rays in the secondary phloem include protein rich albuminous cells. A well-defined pith of parenchyma cells is interrupted by a few large resin ducts.

Gymnosperm Stem: Three Year Pinus

cross section: Pinus stem magnification: 40x During the first year of growth the cutinized epidermis is replaced by protective growth of cork rich periderm. The outer periderm consists of layers of cork cells, the phellem, which produces waterproofing suberin. Cork cells are dead at maturity. Deep to the phellem is a living layer of cork cambium or phellogen and beneath that, layers of cork parenchyma or phelloderm. Many cells in the periderm contain dark staining tannins. The cortex is divided into a thin outer hypodermis of lignified sclerenchyma cells and thicker inner cortex of thin walled parenchyma cells containing chloroplasts. Large resin ducts are surrounded by secretory parenchyma that produces resins and turpentines. Some cells enlarge into dark staining tyloses. Both endoderm and pericycle are inconspicuous. The vascular cylinder or stele in young stems consists of a ring of vascular bundles interspaced with medullary rays of parenchyma cells. Seasonal activity of the cambium replaces the isolated vascular bundles with well-defined annual rings of secondary phloem and xylem. Xylem is endarch with protoxylem found towards center of the stem and younger metaxylem towards the periphery of the stem. Protoxylem consists of annular and spiral tracheids with only tracheids found in metaxylem. True xylem vessels are lacking. Because of the greater production of xylem, the vascular cylinder is dominated by radially arranged rays of secondary xylem interspaced with medullary rays of parenchyma cells. Conspicuous resin ducts are present throughout the xylem. Phloem is endarch but annual growth the of stem makes it difficult to distinguish between older protophloem to the periphery and younger metapholem towards center of the stem. Phloem lacks companion cells, consisting entirely of sieve tubes and phloem parenchyma. Medullary rays in the secondary phloem include protein rich albuminous cells. A well-defined pith of parenchyma cells is interrupted by a few large resin ducts. cross section: Pinus stem magnification: 40x During the first year of growth the cutinized epidermis is replaced by protective growth of cork rich periderm. The outer periderm consists of layers of cork cells, the phellem, which produces waterproofing suberin. Cork cells are dead at maturity. Deep to the phellem is a living layer of cork cambium or phellogen and beneath that, layers of cork parenchyma or phelloderm. Many cells in the periderm contain dark staining tannins. The cortex is divided into a thin outer hypodermis of lignified sclerenchyma cells and thicker inner cortex of thin walled parenchyma cells containing chloroplasts. Large resin ducts are surrounded by secretory parenchyma that produces resins and turpentines. Some cells enlarge into dark staining tyloses. Both endoderm and pericycle are inconspicuous. The vascular cylinder or stele in young stems consists of a ring of vascular bundles interspaced with medullary rays of parenchyma cells. Seasonal activity of the cambium replaces the isolated vascular bundles with well-defined annual rings of secondary phloem and xylem. Xylem is endarch with protoxylem found towards center of the stem and younger metaxylem towards the periphery of the stem. Protoxylem consists of annular and spiral tracheids with only tracheids found in metaxylem. True xylem vessels are lacking. Because of the greater production of xylem, the vascular cylinder is dominated by radially arranged rays of secondary xylem interspaced with medullary rays of parenchyma cells. Conspicuous resin ducts are present throughout the xylem. Phloem is endarch but annual growth the of stem makes it difficult to distinguish between older protophloem to the periphery and younger metapholem towards center of the stem. Phloem lacks companion cells, consisting entirely of sieve tubes and phloem parenchyma. Medullary rays in the secondary phloem include protein rich albuminous cells. A well-defined pith of parenchyma cells is interrupted by a few large resin ducts.

Gymnosperm Stem: Cambium in Two Year Pinus

cross section: Pinus stem magnification: 400x During the first year of growth the cutinized epidermis is replaced by protective growth of cork rich periderm. The outer periderm consists of layers of cork cells, the phellem, which produces waterproofing suberin. Cork cells are dead at maturity. Deep to the phellem is a living layer of cork cambium or phellogen and beneath that, layers of cork parenchyma or phelloderm. Many cells in the periderm contain dark staining tannins. The cortex is divided into a thin outer hypodermis of lignified sclerenchyma cells and thicker inner cortex of thin walled parenchyma cells containing chloroplasts. Large resin ducts are surrounded by secretory parenchyma that produces resins and turpentines. Some cells enlarge into dark staining tyloses. Both endoderm and pericycle are inconspicuous. The vascular cylinder or stele in young stems consists of a ring of vascular bundles interspaced with medullary rays of parenchyma cells. Seasonal activity of the cambium replaces the isolated vascular bundles with well-defined annual rings of secondary phloem and xylem. Xylem is endarch with protoxylem found towards center of the stem and younger metaxylem towards the periphery of the stem. Protoxylem consists of annular and spiral tracheids with only tracheids found in metaxylem. True xylem vessels are lacking. Because of the greater production of xylem, the vascular cylinder is dominated by radially arranged rays of secondary xylem interspaced with medullary rays of parenchyma cells. Conspicuous resin ducts are present throughout the xylem. Phloem is endarch but annual growth the of stem makes it difficult to distinguish between older protophloem to the periphery and younger metapholem towards center of the stem. Phloem lacks companion cells, consisting entirely of sieve tubes and phloem parenchyma. Medullary rays in the secondary phloem include protein rich albuminous cells. A well-defined pith of parenchyma cells is interrupted by a few large resin ducts. cross section: Pinus stem magnification: 400x During the first year of growth the cutinized epidermis is replaced by protective growth of cork rich periderm. The outer periderm consists of layers of cork cells, the phellem, which produces waterproofing suberin. Cork cells are dead at maturity. Deep to the phellem is a living layer of cork cambium or phellogen and beneath that, layers of cork parenchyma or phelloderm. Many cells in the periderm contain dark staining tannins. The cortex is divided into a thin outer hypodermis of lignified sclerenchyma cells and thicker inner cortex of thin walled parenchyma cells containing chloroplasts. Large resin ducts are surrounded by secretory parenchyma that produces resins and turpentines. Some cells enlarge into dark staining tyloses. Both endoderm and pericycle are inconspicuous. The vascular cylinder or stele in young stems consists of a ring of vascular bundles interspaced with medullary rays of parenchyma cells. Seasonal activity of the cambium replaces the isolated vascular bundles with well-defined annual rings of secondary phloem and xylem. Xylem is endarch with protoxylem found towards center of the stem and younger metaxylem towards the periphery of the stem. Protoxylem consists of annular and spiral tracheids with only tracheids found in metaxylem. True xylem vessels are lacking. Because of the greater production of xylem, the vascular cylinder is dominated by radially arranged rays of secondary xylem interspaced with medullary rays of parenchyma cells. Conspicuous resin ducts are present throughout the xylem. Phloem is endarch but annual growth the of stem makes it difficult to distinguish between older protophloem to the periphery and younger metapholem towards center of the stem. Phloem lacks companion cells, consisting entirely of sieve tubes and phloem parenchyma. Medullary rays in the secondary phloem include protein rich albuminous cells. A well-defined pith of parenchyma cells is interrupted by a few large resin ducts.

Gymnosperm Stem: Cork and Cortex in Three Year Pinus

cross section: Pinus stem magnification: 100x During the first year of growth the cutinized epidermis is replaced by protective growth of cork rich periderm. The outer periderm consists of layers of cork cells, the phellem, which produces waterproofing suberin. Cork cells are dead at maturity. Deep to the phellem is a living layer of cork cambium or phellogen and beneath that, layers of cork parenchyma or phelloderm. Many cells in the periderm contain dark staining tannins. The cortex is divided into a thin outer hypodermis of lignified sclerenchyma cells and thicker inner cortex of thin walled parenchyma cells containing chloroplasts. Large resin ducts are surrounded by secretory parenchyma that produces resins and turpentines. Some cells enlarge into dark staining tyloses. Both endoderm and pericycle are inconspicuous. The vascular cylinder or stele in young stems consists of a ring of vascular bundles interspaced with medullary rays of parenchyma cells. Seasonal activity of the cambium replaces the isolated vascular bundles with well-defined annual rings of secondary phloem and xylem. Xylem is endarch with protoxylem found towards center of the stem and younger metaxylem towards the periphery of the stem. Protoxylem consists of annular and spiral tracheids with only tracheids found in metaxylem. True xylem vessels are lacking. Because of the greater production of xylem, the vascular cylinder is dominated by radially arranged rays of secondary xylem interspaced with medullary rays of parenchyma cells. Conspicuous resin ducts are present throughout the xylem. Phloem is endarch but annual growth the of stem makes it difficult to distinguish between older protophloem to the periphery and younger metapholem towards center of the stem. Phloem lacks companion cells, consisting entirely of sieve tubes and phloem parenchyma. Medullary rays in the secondary phloem include protein rich albuminous cells. A well-defined pith of parenchyma cells is interrupted by a few large resin ducts. cross section: Pinus stem magnification: 100x During the first year of growth the cutinized epidermis is replaced by protective growth of cork rich periderm. The outer periderm consists of layers of cork cells, the phellem, which produces waterproofing suberin. Cork cells are dead at maturity. Deep to the phellem is a living layer of cork cambium or phellogen and beneath that, layers of cork parenchyma or phelloderm. Many cells in the periderm contain dark staining tannins. The cortex is divided into a thin outer hypodermis of lignified sclerenchyma cells and thicker inner cortex of thin walled parenchyma cells containing chloroplasts. Large resin ducts are surrounded by secretory parenchyma that produces resins and turpentines. Some cells enlarge into dark staining tyloses. Both endoderm and pericycle are inconspicuous. The vascular cylinder or stele in young stems consists of a ring of vascular bundles interspaced with medullary rays of parenchyma cells. Seasonal activity of the cambium replaces the isolated vascular bundles with well-defined annual rings of secondary phloem and xylem. Xylem is endarch with protoxylem found towards center of the stem and younger metaxylem towards the periphery of the stem. Protoxylem consists of annular and spiral tracheids with only tracheids found in metaxylem. True xylem vessels are lacking. Because of the greater production of xylem, the vascular cylinder is dominated by radially arranged rays of secondary xylem interspaced with medullary rays of parenchyma cells. Conspicuous resin ducts are present throughout the xylem. Phloem is endarch but annual growth the of stem makes it difficult to distinguish between older protophloem to the periphery and younger metapholem towards center of the stem. Phloem lacks companion cells, consisting entirely of sieve tubes and phloem parenchyma. Medullary rays in the secondary phloem include protein rich albuminous cells. A well-defined pith of parenchyma cells is interrupted by a few large resin ducts.

Gymnosperm Stem: Three Year Pinus

cross section: Pinus stem magnification: 40x During the first year of growth the cutinized epidermis is replaced by protective growth of cork rich periderm. The outer periderm consists of layers of cork cells, the phellem, which produces waterproofing suberin. Cork cells are dead at maturity. Deep to the phellem is a living layer of cork cambium or phellogen and beneath that, layers of cork parenchyma or phelloderm. Many cells in the periderm contain dark staining tannins. The cortex is divided into a thin outer hypodermis of lignified sclerenchyma cells and thicker inner cortex of thin walled parenchyma cells containing chloroplasts. Large resin ducts are surrounded by secretory parenchyma that produces resins and turpentines. Some cells enlarge into dark staining tyloses. Both endoderm and pericycle are inconspicuous. The vascular cylinder or stele in young stems consists of a ring of vascular bundles interspaced with medullary rays of parenchyma cells. Seasonal activity of the cambium replaces the isolated vascular bundles with well-defined annual rings of secondary phloem and xylem. Xylem is endarch with protoxylem found towards center of the stem and younger metaxylem towards the periphery of the stem. Protoxylem consists of annular and spiral tracheids with only tracheids found in metaxylem. True xylem vessels are lacking. Because of the greater production of xylem, the vascular cylinder is dominated by radially arranged rays of secondary xylem interspaced with medullary rays of parenchyma cells. Conspicuous resin ducts are present throughout the xylem. Phloem is endarch but annual growth the of stem makes it difficult to distinguish between older protophloem to the periphery and younger metapholem towards center of the stem. Phloem lacks companion cells, consisting entirely of sieve tubes and phloem parenchyma. Medullary rays in the secondary phloem include protein rich albuminous cells. A well-defined pith of parenchyma cells is interrupted by a few large resin ducts. cross section: Pinus stem magnification: 40x During the first year of growth the cutinized epidermis is replaced by protective growth of cork rich periderm. The outer periderm consists of layers of cork cells, the phellem, which produces waterproofing suberin. Cork cells are dead at maturity. Deep to the phellem is a living layer of cork cambium or phellogen and beneath that, layers of cork parenchyma or phelloderm. Many cells in the periderm contain dark staining tannins. The cortex is divided into a thin outer hypodermis of lignified sclerenchyma cells and thicker inner cortex of thin walled parenchyma cells containing chloroplasts. Large resin ducts are surrounded by secretory parenchyma that produces resins and turpentines. Some cells enlarge into dark staining tyloses. Both endoderm and pericycle are inconspicuous. The vascular cylinder or stele in young stems consists of a ring of vascular bundles interspaced with medullary rays of parenchyma cells. Seasonal activity of the cambium replaces the isolated vascular bundles with well-defined annual rings of secondary phloem and xylem. Xylem is endarch with protoxylem found towards center of the stem and younger metaxylem towards the periphery of the stem. Protoxylem consists of annular and spiral tracheids with only tracheids found in metaxylem. True xylem vessels are lacking. Because of the greater production of xylem, the vascular cylinder is dominated by radially arranged rays of secondary xylem interspaced with medullary rays of parenchyma cells. Conspicuous resin ducts are present throughout the xylem. Phloem is endarch but annual growth the of stem makes it difficult to distinguish between older protophloem to the periphery and younger metapholem towards center of the stem. Phloem lacks companion cells, consisting entirely of sieve tubes and phloem parenchyma. Medullary rays in the secondary phloem include protein rich albuminous cells. A well-defined pith of parenchyma cells is interrupted by a few large resin ducts.

Gymnosperm Stem: Cambium in Three Year Pinus

cross section: Pinus stem magnification: 400x During the first year of growth the cutinized epidermis is replaced by protective growth of cork rich periderm. The outer periderm consists of layers of cork cells, the phellem, which produces waterproofing suberin. Cork cells are dead at maturity. Deep to the phellem is a living layer of cork cambium or phellogen and beneath that, layers of cork parenchyma or phelloderm. Many cells in the periderm contain dark staining tannins. The cortex is divided into a thin outer hypodermis of lignified sclerenchyma cells and thicker inner cortex of thin walled parenchyma cells containing chloroplasts. Large resin ducts are surrounded by secretory parenchyma that produces resins and turpentines. Some cells enlarge into dark staining tyloses. Both endoderm and pericycle are inconspicuous. The vascular cylinder or stele in young stems consists of a ring of vascular bundles interspaced with medullary rays of parenchyma cells. Seasonal activity of the cambium replaces the isolated vascular bundles with well-defined annual rings of secondary phloem and xylem. Xylem is endarch with protoxylem found towards center of the stem and younger metaxylem towards the periphery of the stem. Protoxylem consists of annular and spiral tracheids with only tracheids found in metaxylem. True xylem vessels are lacking. Because of the greater production of xylem, the vascular cylinder is dominated by radially arranged rays of secondary xylem interspaced with medullary rays of parenchyma cells. Conspicuous resin ducts are present throughout the xylem. Phloem is endarch but annual growth the of stem makes it difficult to distinguish between older protophloem to the periphery and younger metapholem towards center of the stem. Phloem lacks companion cells, consisting entirely of sieve tubes and phloem parenchyma. Medullary rays in the secondary phloem include protein rich albuminous cells. A well-defined pith of parenchyma cells is interrupted by a few large resin ducts. cross section: Pinus stem magnification: 400x During the first year of growth the cutinized epidermis is replaced by protective growth of cork rich periderm. The outer periderm consists of layers of cork cells, the phellem, which produces waterproofing suberin. Cork cells are dead at maturity. Deep to the phellem is a living layer of cork cambium or phellogen and beneath that, layers of cork parenchyma or phelloderm. Many cells in the periderm contain dark staining tannins. The cortex is divided into a thin outer hypodermis of lignified sclerenchyma cells and thicker inner cortex of thin walled parenchyma cells containing chloroplasts. Large resin ducts are surrounded by secretory parenchyma that produces resins and turpentines. Some cells enlarge into dark staining tyloses. Both endoderm and pericycle are inconspicuous. The vascular cylinder or stele in young stems consists of a ring of vascular bundles interspaced with medullary rays of parenchyma cells. Seasonal activity of the cambium replaces the isolated vascular bundles with well-defined annual rings of secondary phloem and xylem. Xylem is endarch with protoxylem found towards center of the stem and younger metaxylem towards the periphery of the stem. Protoxylem consists of annular and spiral tracheids with only tracheids found in metaxylem. True xylem vessels are lacking. Because of the greater production of xylem, the vascular cylinder is dominated by radially arranged rays of secondary xylem interspaced with medullary rays of parenchyma cells. Conspicuous resin ducts are present throughout the xylem. Phloem is endarch but annual growth the of stem makes it difficult to distinguish between older protophloem to the periphery and younger metapholem towards center of the stem. Phloem lacks companion cells, consisting entirely of sieve tubes and phloem parenchyma. Medullary rays in the secondary phloem include protein rich albuminous cells. A well-defined pith of parenchyma cells is interrupted by a few large resin ducts.

Gymnosperm Stem: Two Year Pinus

cross section: Pinus stem magnification: 40x During the first year of growth the cutinized epidermis is replaced by protective growth of cork rich periderm. The outer periderm consists of layers of cork cells, the phellem, which produces waterproofing suberin. Cork cells are dead at maturity. Deep to the phellem is a living layer of cork cambium or phellogen and beneath that, layers of cork parenchyma or phelloderm. Many cells in the periderm contain dark staining tannins. The cortex is divided into a thin outer hypodermis of lignified sclerenchyma cells and thicker inner cortex of thin walled parenchyma cells containing chloroplasts. Large resin ducts are surrounded by secretory parenchyma that produces resins and turpentines. Some cells enlarge into dark staining tyloses. Both endoderm and pericycle are inconspicuous. The vascular cylinder or stele in young stems consists of a ring of vascular bundles interspaced with medullary rays of parenchyma cells. Seasonal activity of the cambium replaces the isolated vascular bundles with well-defined annual rings of secondary phloem and xylem. Xylem is endarch with protoxylem found towards center of the stem and younger metaxylem towards the periphery of the stem. Protoxylem consists of annular and spiral tracheids with only tracheids found in metaxylem. True xylem vessels are lacking. Because of the greater production of xylem, the vascular cylinder is dominated by radially arranged rays of secondary xylem interspaced with medullary rays of parenchyma cells. Conspicuous resin ducts are present throughout the xylem. Phloem is endarch but annual growth the of stem makes it difficult to distinguish between older protophloem to the periphery and younger metapholem towards center of the stem. Phloem lacks companion cells, consisting entirely of sieve tubes and phloem parenchyma. Medullary rays in the secondary phloem include protein rich albuminous cells. A well-defined pith of parenchyma cells is interrupted by a few large resin ducts. cross section: Pinus stem magnification: 40x During the first year of growth the cutinized epidermis is replaced by protective growth of cork rich periderm. The outer periderm consists of layers of cork cells, the phellem, which produces waterproofing suberin. Cork cells are dead at maturity. Deep to the phellem is a living layer of cork cambium or phellogen and beneath that, layers of cork parenchyma or phelloderm. Many cells in the periderm contain dark staining tannins. The cortex is divided into a thin outer hypodermis of lignified sclerenchyma cells and thicker inner cortex of thin walled parenchyma cells containing chloroplasts. Large resin ducts are surrounded by secretory parenchyma that produces resins and turpentines. Some cells enlarge into dark staining tyloses. Both endoderm and pericycle are inconspicuous. The vascular cylinder or stele in young stems consists of a ring of vascular bundles interspaced with medullary rays of parenchyma cells. Seasonal activity of the cambium replaces the isolated vascular bundles with well-defined annual rings of secondary phloem and xylem. Xylem is endarch with protoxylem found towards center of the stem and younger metaxylem towards the periphery of the stem. Protoxylem consists of annular and spiral tracheids with only tracheids found in metaxylem. True xylem vessels are lacking. Because of the greater production of xylem, the vascular cylinder is dominated by radially arranged rays of secondary xylem interspaced with medullary rays of parenchyma cells. Conspicuous resin ducts are present throughout the xylem. Phloem is endarch but annual growth the of stem makes it difficult to distinguish between older protophloem to the periphery and younger metapholem towards center of the stem. Phloem lacks companion cells, consisting entirely of sieve tubes and phloem parenchyma. Medullary rays in the secondary phloem include protein rich albuminous cells. A well-defined pith of parenchyma cells is interrupted by a few large resin ducts.

Gymnosperm Stem: Pith in Two Year Pinus

cross section: Pinus stem magnification: 400x During the first year of growth the cutinized epidermis is replaced by protective growth of cork rich periderm. The outer periderm consists of layers of cork cells, the phellem, which produces waterproofing suberin. Cork cells are dead at maturity. Deep to the phellem is a living layer of cork cambium or phellogen and beneath that, layers of cork parenchyma or phelloderm. Many cells in the periderm contain dark staining tannins. The cortex is divided into a thin outer hypodermis of lignified sclerenchyma cells and thicker inner cortex of thin walled parenchyma cells containing chloroplasts. Large resin ducts are surrounded by secretory parenchyma that produces resins and turpentines. Some cells enlarge into dark staining tyloses. Both endoderm and pericycle are inconspicuous. The vascular cylinder or stele in young stems consists of a ring of vascular bundles interspaced with medullary rays of parenchyma cells. Seasonal activity of the cambium replaces the isolated vascular bundles with well-defined annual rings of secondary phloem and xylem. Xylem is endarch with protoxylem found towards center of the stem and younger metaxylem towards the periphery of the stem. Protoxylem consists of annular and spiral tracheids with only tracheids found in metaxylem. True xylem vessels are lacking. Because of the greater production of xylem, the vascular cylinder is dominated by radially arranged rays of secondary xylem interspaced with medullary rays of parenchyma cells. Conspicuous resin ducts are present throughout the xylem. Phloem is endarch but annual growth the of stem makes it difficult to distinguish between older protophloem to the periphery and younger metapholem towards center of the stem. Phloem lacks companion cells, consisting entirely of sieve tubes and phloem parenchyma. Medullary rays in the secondary phloem include protein rich albuminous cells. A well-defined pith of parenchyma cells is interrupted by a few large resin ducts. cross section: Pinus stem magnification: 400x During the first year of growth the cutinized epidermis is replaced by protective growth of cork rich periderm. The outer periderm consists of layers of cork cells, the phellem, which produces waterproofing suberin. Cork cells are dead at maturity. Deep to the phellem is a living layer of cork cambium or phellogen and beneath that, layers of cork parenchyma or phelloderm. Many cells in the periderm contain dark staining tannins. The cortex is divided into a thin outer hypodermis of lignified sclerenchyma cells and thicker inner cortex of thin walled parenchyma cells containing chloroplasts. Large resin ducts are surrounded by secretory parenchyma that produces resins and turpentines. Some cells enlarge into dark staining tyloses. Both endoderm and pericycle are inconspicuous. The vascular cylinder or stele in young stems consists of a ring of vascular bundles interspaced with medullary rays of parenchyma cells. Seasonal activity of the cambium replaces the isolated vascular bundles with well-defined annual rings of secondary phloem and xylem. Xylem is endarch with protoxylem found towards center of the stem and younger metaxylem towards the periphery of the stem. Protoxylem consists of annular and spiral tracheids with only tracheids found in metaxylem. True xylem vessels are lacking. Because of the greater production of xylem, the vascular cylinder is dominated by radially arranged rays of secondary xylem interspaced with medullary rays of parenchyma cells. Conspicuous resin ducts are present throughout the xylem. Phloem is endarch but annual growth the of stem makes it difficult to distinguish between older protophloem to the periphery and younger metapholem towards center of the stem. Phloem lacks companion cells, consisting entirely of sieve tubes and phloem parenchyma. Medullary rays in the secondary phloem include protein rich albuminous cells. A well-defined pith of parenchyma cells is interrupted by a few large resin ducts.

Gymnosperm Stem: Medullary Rays in Three Year Pinus

cross section: Pinus stem magnification: 100x During the first year of growth the cutinized epidermis is replaced by protective growth of cork rich periderm. The outer periderm consists of layers of cork cells, the phellem, which produces waterproofing suberin. Cork cells are dead at maturity. Deep to the phellem is a living layer of cork cambium or phellogen and beneath that, layers of cork parenchyma or phelloderm. Many cells in the periderm contain dark staining tannins. The cortex is divided into a thin outer hypodermis of lignified sclerenchyma cells and thicker inner cortex of thin walled parenchyma cells containing chloroplasts. Large resin ducts are surrounded by secretory parenchyma that produces resins and turpentines. Some cells enlarge into dark staining tyloses. Both endoderm and pericycle are inconspicuous. The vascular cylinder or stele in young stems consists of a ring of vascular bundles interspaced with medullary rays of parenchyma cells. Seasonal activity of the cambium replaces the isolated vascular bundles with well-defined annual rings of secondary phloem and xylem. Xylem is endarch with protoxylem found towards center of the stem and younger metaxylem towards the periphery of the stem. Protoxylem consists of annular and spiral tracheids with only tracheids found in metaxylem. True xylem vessels are lacking. Because of the greater production of xylem, the vascular cylinder is dominated by radially arranged rays of secondary xylem interspaced with medullary rays of parenchyma cells. Conspicuous resin ducts are present throughout the xylem. Phloem is endarch but annual growth the of stem makes it difficult to distinguish between older protophloem to the periphery and younger metapholem towards center of the stem. Phloem lacks companion cells, consisting entirely of sieve tubes and phloem parenchyma. Medullary rays in the secondary phloem include protein rich albuminous cells. A well-defined pith of parenchyma cells is interrupted by a few large resin ducts. cross section: Pinus stem magnification: 100x During the first year of growth the cutinized epidermis is replaced by protective growth of cork rich periderm. The outer periderm consists of layers of cork cells, the phellem, which produces waterproofing suberin. Cork cells are dead at maturity. Deep to the phellem is a living layer of cork cambium or phellogen and beneath that, layers of cork parenchyma or phelloderm. Many cells in the periderm contain dark staining tannins. The cortex is divided into a thin outer hypodermis of lignified sclerenchyma cells and thicker inner cortex of thin walled parenchyma cells containing chloroplasts. Large resin ducts are surrounded by secretory parenchyma that produces resins and turpentines. Some cells enlarge into dark staining tyloses. Both endoderm and pericycle are inconspicuous. The vascular cylinder or stele in young stems consists of a ring of vascular bundles interspaced with medullary rays of parenchyma cells. Seasonal activity of the cambium replaces the isolated vascular bundles with well-defined annual rings of secondary phloem and xylem. Xylem is endarch with protoxylem found towards center of the stem and younger metaxylem towards the periphery of the stem. Protoxylem consists of annular and spiral tracheids with only tracheids found in metaxylem. True xylem vessels are lacking. Because of the greater production of xylem, the vascular cylinder is dominated by radially arranged rays of secondary xylem interspaced with medullary rays of parenchyma cells. Conspicuous resin ducts are present throughout the xylem. Phloem is endarch but annual growth the of stem makes it difficult to distinguish between older protophloem to the periphery and younger metapholem towards center of the stem. Phloem lacks companion cells, consisting entirely of sieve tubes and phloem parenchyma. Medullary rays in the secondary phloem include protein rich albuminous cells. A well-defined pith of parenchyma cells is interrupted by a few large resin ducts.

Gymnosperm Stem: Pith in Three Year Pinus

cross section: Pinus stem magnification: 100x During the first year of growth the cutinized epidermis is replaced by protective growth of cork rich periderm. The outer periderm consists of layers of cork cells, the phellem, which produces waterproofing suberin. Cork cells are dead at maturity. Deep to the phellem is a living layer of cork cambium or phellogen and beneath that, layers of cork parenchyma or phelloderm. Many cells in the periderm contain dark staining tannins. The cortex is divided into a thin outer hypodermis of lignified sclerenchyma cells and thicker inner cortex of thin walled parenchyma cells containing chloroplasts. Large resin ducts are surrounded by secretory parenchyma that produces resins and turpentines. Some cells enlarge into dark staining tyloses. Both endoderm and pericycle are inconspicuous. The vascular cylinder or stele in young stems consists of a ring of vascular bundles interspaced with medullary rays of parenchyma cells. Seasonal activity of the cambium replaces the isolated vascular bundles with well-defined annual rings of secondary phloem and xylem. Xylem is endarch with protoxylem found towards center of the stem and younger metaxylem towards the periphery of the stem. Protoxylem consists of annular and spiral tracheids with only tracheids found in metaxylem. True xylem vessels are lacking. Because of the greater production of xylem, the vascular cylinder is dominated by radially arranged rays of secondary xylem interspaced with medullary rays of parenchyma cells. Conspicuous resin ducts are present throughout the xylem. Phloem is endarch but annual growth the of stem makes it difficult to distinguish between older protophloem to the periphery and younger metapholem towards center of the stem. Phloem lacks companion cells, consisting entirely of sieve tubes and phloem parenchyma. Medullary rays in the secondary phloem include protein rich albuminous cells. A well-defined pith of parenchyma cells is interrupted by a few large resin ducts. cross section: Pinus stem magnification: 100x During the first year of growth the cutinized epidermis is replaced by protective growth of cork rich periderm. The outer periderm consists of layers of cork cells, the phellem, which produces waterproofing suberin. Cork cells are dead at maturity. Deep to the phellem is a living layer of cork cambium or phellogen and beneath that, layers of cork parenchyma or phelloderm. Many cells in the periderm contain dark staining tannins. The cortex is divided into a thin outer hypodermis of lignified sclerenchyma cells and thicker inner cortex of thin walled parenchyma cells containing chloroplasts. Large resin ducts are surrounded by secretory parenchyma that produces resins and turpentines. Some cells enlarge into dark staining tyloses. Both endoderm and pericycle are inconspicuous. The vascular cylinder or stele in young stems consists of a ring of vascular bundles interspaced with medullary rays of parenchyma cells. Seasonal activity of the cambium replaces the isolated vascular bundles with well-defined annual rings of secondary phloem and xylem. Xylem is endarch with protoxylem found towards center of the stem and younger metaxylem towards the periphery of the stem. Protoxylem consists of annular and spiral tracheids with only tracheids found in metaxylem. True xylem vessels are lacking. Because of the greater production of xylem, the vascular cylinder is dominated by radially arranged rays of secondary xylem interspaced with medullary rays of parenchyma cells. Conspicuous resin ducts are present throughout the xylem. Phloem is endarch but annual growth the of stem makes it difficult to distinguish between older protophloem to the periphery and younger metapholem towards center of the stem. Phloem lacks companion cells, consisting entirely of sieve tubes and phloem parenchyma. Medullary rays in the secondary phloem include protein rich albuminous cells. A well-defined pith of parenchyma cells is interrupted by a few large resin ducts.

Gymnosperm Stem: Annual Rings in Three Year Pinus

cross section: Pinus stem magnification: 100x During the first year of growth the cutinized epidermis is replaced by protective growth of cork rich periderm. The outer periderm consists of layers of cork cells, the phellem, which produces waterproofing suberin. Cork cells are dead at maturity. Deep to the phellem is a living layer of cork cambium or phellogen and beneath that, layers of cork parenchyma or phelloderm. Many cells in the periderm contain dark staining tannins. The cortex is divided into a thin outer hypodermis of lignified sclerenchyma cells and thicker inner cortex of thin walled parenchyma cells containing chloroplasts. Large resin ducts are surrounded by secretory parenchyma that produces resins and turpentines. Some cells enlarge into dark staining tyloses. Both endoderm and pericycle are inconspicuous. The vascular cylinder or stele in young stems consists of a ring of vascular bundles interspaced with medullary rays of parenchyma cells. Seasonal activity of the cambium replaces the isolated vascular bundles with well-defined annual rings of secondary phloem and xylem. Xylem is endarch with protoxylem found towards center of the stem and younger metaxylem towards the periphery of the stem. Protoxylem consists of annular and spiral tracheids with only tracheids found in metaxylem. True xylem vessels are lacking. Because of the greater production of xylem, the vascular cylinder is dominated by radially arranged rays of secondary xylem interspaced with medullary rays of parenchyma cells. Conspicuous resin ducts are present throughout the xylem. Phloem is endarch but annual growth the of stem makes it difficult to distinguish between older protophloem to the periphery and younger metapholem towards center of the stem. Phloem lacks companion cells, consisting entirely of sieve tubes and phloem parenchyma. Medullary rays in the secondary phloem include protein rich albuminous cells. A well-defined pith of parenchyma cells is interrupted by a few large resin ducts. cross section: Pinus stem magnification: 100x During the first year of growth the cutinized epidermis is replaced by protective growth of cork rich periderm. The outer periderm consists of layers of cork cells, the phellem, which produces waterproofing suberin. Cork cells are dead at maturity. Deep to the phellem is a living layer of cork cambium or phellogen and beneath that, layers of cork parenchyma or phelloderm. Many cells in the periderm contain dark staining tannins. The cortex is divided into a thin outer hypodermis of lignified sclerenchyma cells and thicker inner cortex of thin walled parenchyma cells containing chloroplasts. Large resin ducts are surrounded by secretory parenchyma that produces resins and turpentines. Some cells enlarge into dark staining tyloses. Both endoderm and pericycle are inconspicuous. The vascular cylinder or stele in young stems consists of a ring of vascular bundles interspaced with medullary rays of parenchyma cells. Seasonal activity of the cambium replaces the isolated vascular bundles with well-defined annual rings of secondary phloem and xylem. Xylem is endarch with protoxylem found towards center of the stem and younger metaxylem towards the periphery of the stem. Protoxylem consists of annular and spiral tracheids with only tracheids found in metaxylem. True xylem vessels are lacking. Because of the greater production of xylem, the vascular cylinder is dominated by radially arranged rays of secondary xylem interspaced with medullary rays of parenchyma cells. Conspicuous resin ducts are present throughout the xylem. Phloem is endarch but annual growth the of stem makes it difficult to distinguish between older protophloem to the periphery and younger metapholem towards center of the stem. Phloem lacks companion cells, consisting entirely of sieve tubes and phloem parenchyma. Medullary rays in the secondary phloem include protein rich albuminous cells. A well-defined pith of parenchyma cells is interrupted by a few large resin ducts.

Gymnosperm Stem: Cortical Resin Duct in Three Year Pinus

cross section: Pinus stem magnification: 100x During the first year of growth the cutinized epidermis is replaced by protective growth of cork rich periderm. The outer periderm consists of layers of cork cells, the phellem, which produces waterproofing suberin. Cork cells are dead at maturity. Deep to the phellem is a living layer of cork cambium or phellogen and beneath that, layers of cork parenchyma or phelloderm. Many cells in the periderm contain dark staining tannins. The cortex is divided into a thin outer hypodermis of lignified sclerenchyma cells and thicker inner cortex of thin walled parenchyma cells containing chloroplasts. Large resin ducts are surrounded by secretory parenchyma that produces resins and turpentines. Some cells enlarge into dark staining tyloses. Both endoderm and pericycle are inconspicuous. The vascular cylinder or stele in young stems consists of a ring of vascular bundles interspaced with medullary rays of parenchyma cells. Seasonal activity of the cambium replaces the isolated vascular bundles with well-defined annual rings of secondary phloem and xylem. Xylem is endarch with protoxylem found towards center of the stem and younger metaxylem towards the periphery of the stem. Protoxylem consists of annular and spiral tracheids with only tracheids found in metaxylem. True xylem vessels are lacking. Because of the greater production of xylem, the vascular cylinder is dominated by radially arranged rays of secondary xylem interspaced with medullary rays of parenchyma cells. Conspicuous resin ducts are present throughout the xylem. Phloem is endarch but annual growth the of stem makes it difficult to distinguish between older protophloem to the periphery and younger metapholem towards center of the stem. Phloem lacks companion cells, consisting entirely of sieve tubes and phloem parenchyma. Medullary rays in the secondary phloem include protein rich albuminous cells. A well-defined pith of parenchyma cells is interrupted by a few large resin ducts. cross section: Pinus stem magnification: 100x During the first year of growth the cutinized epidermis is replaced by protective growth of cork rich periderm. The outer periderm consists of layers of cork cells, the phellem, which produces waterproofing suberin. Cork cells are dead at maturity. Deep to the phellem is a living layer of cork cambium or phellogen and beneath that, layers of cork parenchyma or phelloderm. Many cells in the periderm contain dark staining tannins. The cortex is divided into a thin outer hypodermis of lignified sclerenchyma cells and thicker inner cortex of thin walled parenchyma cells containing chloroplasts. Large resin ducts are surrounded by secretory parenchyma that produces resins and turpentines. Some cells enlarge into dark staining tyloses. Both endoderm and pericycle are inconspicuous. The vascular cylinder or stele in young stems consists of a ring of vascular bundles interspaced with medullary rays of parenchyma cells. Seasonal activity of the cambium replaces the isolated vascular bundles with well-defined annual rings of secondary phloem and xylem. Xylem is endarch with protoxylem found towards center of the stem and younger metaxylem towards the periphery of the stem. Protoxylem consists of annular and spiral tracheids with only tracheids found in metaxylem. True xylem vessels are lacking. Because of the greater production of xylem, the vascular cylinder is dominated by radially arranged rays of secondary xylem interspaced with medullary rays of parenchyma cells. Conspicuous resin ducts are present throughout the xylem. Phloem is endarch but annual growth the of stem makes it difficult to distinguish between older protophloem to the periphery and younger metapholem towards center of the stem. Phloem lacks companion cells, consisting entirely of sieve tubes and phloem parenchyma. Medullary rays in the secondary phloem include protein rich albuminous cells. A well-defined pith of parenchyma cells is interrupted by a few large resin ducts.

Gymnosperm Stem: Phloem in Three Year Pinus

cross section: Pinus stem magnification: 100x During the first year of growth the cutinized epidermis is replaced by protective growth of cork rich periderm. The outer periderm consists of layers of cork cells, the phellem, which produces waterproofing suberin. Cork cells are dead at maturity. Deep to the phellem is a living layer of cork cambium or phellogen and beneath that, layers of cork parenchyma or phelloderm. Many cells in the periderm contain dark staining tannins. The cortex is divided into a thin outer hypodermis of lignified sclerenchyma cells and thicker inner cortex of thin walled parenchyma cells containing chloroplasts. Large resin ducts are surrounded by secretory parenchyma that produces resins and turpentines. Some cells enlarge into dark staining tyloses. Both endoderm and pericycle are inconspicuous. The vascular cylinder or stele in young stems consists of a ring of vascular bundles interspaced with medullary rays of parenchyma cells. Seasonal activity of the cambium replaces the isolated vascular bundles with well-defined annual rings of secondary phloem and xylem. Xylem is endarch with protoxylem found towards center of the stem and younger metaxylem towards the periphery of the stem. Protoxylem consists of annular and spiral tracheids with only tracheids found in metaxylem. True xylem vessels are lacking. Because of the greater production of xylem, the vascular cylinder is dominated by radially arranged rays of secondary xylem interspaced with medullary rays of parenchyma cells. Conspicuous resin ducts are present throughout the xylem. Phloem is endarch but annual growth the of stem makes it difficult to distinguish between older protophloem to the periphery and younger metapholem towards center of the stem. Phloem lacks companion cells, consisting entirely of sieve tubes and phloem parenchyma. Medullary rays in the secondary phloem include protein rich albuminous cells. A well-defined pith of parenchyma cells is interrupted by a few large resin ducts. cross section: Pinus stem magnification: 100x During the first year of growth the cutinized epidermis is replaced by protective growth of cork rich periderm. The outer periderm consists of layers of cork cells, the phellem, which produces waterproofing suberin. Cork cells are dead at maturity. Deep to the phellem is a living layer of cork cambium or phellogen and beneath that, layers of cork parenchyma or phelloderm. Many cells in the periderm contain dark staining tannins. The cortex is divided into a thin outer hypodermis of lignified sclerenchyma cells and thicker inner cortex of thin walled parenchyma cells containing chloroplasts. Large resin ducts are surrounded by secretory parenchyma that produces resins and turpentines. Some cells enlarge into dark staining tyloses. Both endoderm and pericycle are inconspicuous. The vascular cylinder or stele in young stems consists of a ring of vascular bundles interspaced with medullary rays of parenchyma cells. Seasonal activity of the cambium replaces the isolated vascular bundles with well-defined annual rings of secondary phloem and xylem. Xylem is endarch with protoxylem found towards center of the stem and younger metaxylem towards the periphery of the stem. Protoxylem consists of annular and spiral tracheids with only tracheids found in metaxylem. True xylem vessels are lacking. Because of the greater production of xylem, the vascular cylinder is dominated by radially arranged rays of secondary xylem interspaced with medullary rays of parenchyma cells. Conspicuous resin ducts are present throughout the xylem. Phloem is endarch but annual growth the of stem makes it difficult to distinguish between older protophloem to the periphery and younger metapholem towards center of the stem. Phloem lacks companion cells, consisting entirely of sieve tubes and phloem parenchyma. Medullary rays in the secondary phloem include protein rich albuminous cells. A well-defined pith of parenchyma cells is interrupted by a few large resin ducts.

Angiosperm Morphology: The Closed and Collateral Vascular Bundle in Zea

cross section:Zea leaf common name: corn magnification: 400x The iso-bilateral leaf of Zea is typical of most monocots. Both upper and lower epidermis are uniseriate and well cutinized. Within the upper, or adaxial, epidermis, large white bulliform cells shrink, allowing the leaf to roll during drought. Stomata are present on both surfaces with guard cells perched above small round substomatal chambers. As with most monocots the mesophyll is unspecialized, being composed of compactly arranged somewhat round chlorenchyma cells. Numerous small and occasionally large vascular bundles are arranged in parallel series along the length of the leaf. The vascular bundles are collateral and closed with xylem of vessels and tracheids towards the adaxial surface and phloem of sieve tubes and companion cells towards the abaxial surface. Cambium is not present. Within each bundle a xylem of two oval metaxylem and a single large protoxylem cavity can be seen. Each vascular bundle is wraped by a bundle sheath of thin walled parenchyma cells. Larger bundles are supported towards both surfaces by masses of sclerenchyma that interrupt the mesophyll to form a patchy hypodermis. cross section:Zea leaf common name: corn magnification: 400x The iso-bilateral leaf of Zea is typical of most monocots. Both upper and lower epidermis are uniseriate and well cutinized. Within the upper, or adaxial, epidermis, large white bulliform cells shrink, allowing the leaf to roll during drought. Stomata are present on both surfaces with guard cells perched above small round substomatal chambers. As with most monocots the mesophyll is unspecialized, being composed of compactly arranged somewhat round chlorenchyma cells. Numerous small and occasionally large vascular bundles are arranged in parallel series along the length of the leaf. The vascular bundles are collateral and closed with xylem of vessels and tracheids towards the adaxial surface and phloem of sieve tubes and companion cells towards the abaxial surface. Cambium is not present. Within each bundle a xylem of two oval metaxylem and a single large protoxylem cavity can be seen. Each vascular bundle is wraped by a bundle sheath of thin walled parenchyma cells. Larger bundles are supported towards both surfaces by masses of sclerenchyma that interrupt the mesophyll to form a patchy hypodermis.

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