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Industrial air conditioning ducts

Rusty Metal Pipe In Construction Site. Rusty Metal Pipe In Construction Site

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.

Gallbladder ejection fraction nuclear medicine

All phases of gallbladder before ejection fraction examination ,there are immediate image of liver after injection of isotope ,15,30 ,45,60 minutes images with tracer in blue color reveal ducts of the liver and gallbladder and then appears in intestine. All phases of gallbladder before ejection fraction examination ,there are immediate image of liver after injection of isotope ,15,30 ,45,60 minutes images with tracer in blue color reveal ducts of the liver and gallbladder and then appears in intestine

Photograph of the blue pipes

It is an old outlet on the wall

Pipe road red and white

A shot of a old rusty Cannon heater.

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.

Gymnosperm Stem: Resin Duct in Three Year Pinus

cross section: Pinus stem magnification: 100x 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. cross section: Pinus stem magnification: 100x 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.

Ventilation Ducts

Ventilation Ducts

Large metal heating ducts

Large metal heating 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.

Industrial Pipes Outside Building with Blue Sky

Industrial Pipes Outside Building with Blue Sky Vertical

liver and gallbladder

Nuclear hida scan for diagnostic of ejection fraction of gallbladder , liver has red color ,ducts of liver contain green yellow black and blue colors, gallbladder in the form of egg black color ,contour yellow and green. Nuclear hida scan for diagnostic of ejection fraction of gallbladder , liver has red color ,ducts of liver contain green yellow black and blue colors, gallbladder in the form of egg black color ,contour yellow and green

Checking Air Ducts in Home HVAC System

Checking Air Ducts in Home HVAC System

Photo of the blue pipes

Air-conditioning Ducts

Air-conditioning Ducts

Photograph of the blue pipes

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.

Telecomunications Cables

Telecommunications cables in the basement. Telecommunications cables in the basement

White ceining and windows of industrial space

Bile

Concrete pipe in construction site

Concrete pipe with beam gantry crane in construction site. Concrete pipe with beam gantry crane in construction site

Radiator fins closeup

Closeup of a vintage farm tractor engine radiator cooling fins. Closeup of a vintage farm tractor engine radiator cooling fins.

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.

Old brick chimney

Old brick chimney in the blue sky

Gallbaldder Hida ,nuclear medicine

Yellow- blue tracer filling gallbladder and upper part of intestine ,most popular scan for revealing gallbladder pathology in nuclear medicine. Yellow- blue tracer filling gallbladder and upper part of intestine ,most popular scan for revealing gallbladder pathology in nuclear medicine

Black and white detail shot of air ducts or vents - look like chimneys

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.

Seven rusty hood fins

Closeup of a vintage farm tractor engine cowl, cooling vents. Closeup of a vintage farm tractor engine cowl, cooling vents

Industrial tube air-conditioning, background

Industrial tube air-conditioning, background

Air conditioning ducts

Air conditioning ducts

Air ducts in a industry

Air ducts in a industry

Ink 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.

Vent and air ducts for air conditioning system

Vent and air ducts for air conditioning system

Photo of the ceramic pipes

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: 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.

A locked door with chicken wire embedded in the glass blocks access to a deserted corridor with exposed ductwork. The location is Kansas City's historic Union Station, which is on the National Register of Historic Places. A locked door with chicken wire embedded in the glass blocks access to a deserted corridor with exposed ductwork. The location is Kansas City's historic Union Station, which is on the National Register of Historic Places

Gymnosperm Stem: Three Year Pinus

cross section: Pinus stem magnification: 100x 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. cross section: Pinus stem magnification: 100x 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.

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.

Residential home construction attic view

Residential home construction attic view

Gymnosperm Stem: Epidermis and Cortex 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. 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.

Steel Door with Ductwork

Shipping and receiving area door. Shipping and receiving area door

Stack of many concrete drainage pipe

Stack of many concrete drainage pipe on wall in construction site

Vents in the wal

The vents in the wall of the building industry.

Gymnosperm Stem: Medullary Rays Three Year Pinus

cross section: Pinus stem magnification: 100x 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. cross section: Pinus stem magnification: 100x 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.

Four rusty hood fins and hole

Closeup of a vintage farm tractor engine cowl, cooling vents, with large open hole. Closeup of a vintage farm tractor engine cowl, cooling vents, with large open hole

Red tractor grill fins

Red grill fins closeup from front of old vintage tractor. Painted red over rusty iron. Red grill fins closeup from front of old vintage tractor. Painted red over rusty iron.

Photo of the blue pipes

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: 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.

Circular red heat sink isolated on white background.

Bunch of new pipes with label

Bunch of new pipes on a warehouse platform. Bunch of new pipes on a warehouse platform

System of ventilating pipes

System of ventilating pipes

The big productive industrial air-conditioner

Worker holding blue pipe

Worker holding blue pipe

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.

The big productive industrial air-conditioner

There are black steel pipes on the harbor

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