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''Pinus longaeva'', the Great Basin bristlecone pine, is a long-living species of tree found in the higher mountains of the southwest United States. The species is one of three closely related trees known as bristlecone pines and is sometimes known as the Intermountain or Western bristlecone pine. One member of this species, at years old, is the oldest known living non-clonal organism on Earth.〔(【引用サイトリンク】title=Oldlist )〕 ==Physical characteristics== It is a medium-size tree, reaching tall and with a trunk diameter of up to . The bark is bright orange-yellow, thin and scaly at the base of the trunk. The leaves ('needles') are in fascicles of five, stout, long, deep green to blue-green on the outer face, with stomata confined to a bright white band on the inner surfaces. The leaves show the longest persistence of any plant, with some remaining green for 45 years (Ewers & Schmid 1981). These ancient trees have a gnarled and stunted appearance, especially those found at high altitudes,〔 and have reddish-brown bark with deep fissures.〔(【引用サイトリンク】title=The Gymnosperm Database )〕 As the tree ages, much of its vascular cambium layer may die. In very old specimens, often only a narrow strip of living tissue connects the roots to a handful of live branches. The cones are ovoid-cylindrical, long and broad when closed, green or purple at first, ripening orange-buff when 16 months old, with numerous thin, fragile scales, each scale with a bristle-like spine long. The cones open to broad when mature, releasing the seeds immediately after opening. The seeds are long, with a wing; they are mostly dispersed by the wind, but some are also dispersed by Clark's nutcrackers. ''Pinus longaeva'' differs from ''Pinus aristata'' in that the needles of ''P. longaeva'' always have two resin canals, and these are not interrupted and broken, so it lacks the characteristic small white resin flecks appearing on the needles in ''P. aristata''. ''P. longaeva'' differs from the foxtail pine because the cone bristles in ''P. longaeva'' are over long, and the cones have a more rounded (not conic) base. The green pine needles give the twisted branches a bottle-brush appearance. The name bristlecone pine refers to the dark purple female cones that bear incurved prickles on their surface.〔(【引用サイトリンク】title=The Ancient Bristlecone Pine )〕 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Pinus longaeva」の詳細全文を読む スポンサード リンク
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