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Posted by : Aron
вторник, 19 февруари 2013 г.
Picea sitchensis
From Wikipedia, the free encyclopedia
Picea sitchensis Sitka spruce | |
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Quinault Lake Spruce, the largest member of the species according to American Forest by points | |
Conservation status | |
Least Concern (IUCN 2.3) | |
Scientific classification | |
Kingdom: | Plantae |
Division: | Pinophyta |
Class: | Pinopsida |
Order: | Pinales |
Family: | Pinaceae |
Genus: | Picea |
Species: | P. sitchensis |
Binomial name | |
Picea sitchensis (Bong.) Carr. | |
Range |
Picea sitchensis, the Sitka spruce, is a large coniferous evergreen tree growing up to 80 m tall,[1] and with a trunk diameter of up to 5 m, exceptionally to 6–7 m diameter[citation needed]. It is by far the largest species of spruce; and the fifth largest conifer in the world (behind giant sequoia, coast redwood, kauri and western redcedar);[2] and the third tallest conifer species (after coast redwood and coast Douglas-fir). The Sitka spruce is one of the few species documented to reach 300 feet in height.[3] It acquires its name from the community of Sitka, Alaska.
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[edit]Description
Foliage, mature seed cone and (center) old pollen cone
The bark is thin and scaly, flaking off in small circular plates 5–20 cm across. The crown is broad conic in young trees, becoming cylindric in older trees; old trees may have no branches in the lowest 30–40 m. The shoots are very pale buff-brown, almost white, and glabrous (hairless) but with prominent pulvini. The leaves are stiff, sharp and needle-like, 15–25 mm long, flattened in cross-section, dark glaucous blue-green above with two or three thin lines of stomata, and blue-white below with two dense bands of stomata.
The cones are pendulous, slender cylindrical, 6–10 cm long [4] and 2 cm broad when closed, opening to 3 cm broad. They have thin, flexible scales 15–20 mm long; the bracts just above the scales are the longest of any spruce, occasionally just exserted and visible on the closed cones. They are green or reddish,
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