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''Picea breweriana'', know as Brewer's weeping spruce, Brewer spruce or weeping spruce, is a species of spruce native to western North America, where it is one of the rarest on the continent, endemic to the Klamath Mountains of southwest Oregon and northwest California. The specific epithet ''breweriana'' is in honor of the American botanist William Henry Brewer. DNA analyses〔Ran, J.-H., Wei, X.-X. & Wang, X.-Q. 2006. Molecular phylogeny and biogeography of ''Picea'' (Pinaceae): Implications for phylogeographical studies using cytoplasmic haplotypes. ''Mol Phylogenet Evol.'' 41(2): 405–19.〕〔Sigurgeirsson, A. & Szmidt, A.E. 1993. Phylogenetic and biogeographic implications of chloroplast DNA variation in Picea. ''Nordic Journal of Botany'' 13(3): 233–246.〕 have shown that ''Picea breweriana'' has a basal position in the ''Picea'' clade,〔 suggesting that ''Picea'' originated in North America. It grows at moderately high altitudes, from 1000–2700 m.〔Farjon, A. (1990). ''Pinaceae. Drawings and Descriptions of the Genera''. Koeltz Scientific Books ISBN 3-87429-298-3.〕〔Rushforth, K. (1987). ''Conifers''. Helm ISBN 0-7470-2801-X.〕〔Gymnosperm Database: (''Picea breweriana'' )〕〔US Forest Service Silvics Manual: (''Picea breweriana'' )〕 It is a large evergreen coniferous tree growing to 20–40 m tall, exceptionally 54 m, and with a trunk diameter of up to 1.5 m. The bark is thin and scaly, and purple-gray in color. The crown is very distinct, distinguished by level branches with vertically pendulous branchlets, each branch forming a 'curtain' of foliage. The pendulous foliage only develops when the tree grows to about 1.5–2 m tall; young trees smaller than this (up to about 10–20 years old) are open-crowned with sparse, level branchlets. The shoots are orange-brown, with dense short pubescence about 0.2 mm long and very rough with pulvini 1–2 mm long. The leaves are borne singly on the pulvini, and are needle-like, 15–35 mm long, flattened in cross-section, glossy dark green above, and with two bands of white stomata below.〔〔 The cones are longer than most other North American spruces, pendulous, cylindrical, 8–15 cm long and 2 cm broad when closed, opening to 3–4 cm broad. They have smoothly rounded, thin, flexible scales 2 cm long. The immature cones are dark purple, maturing red-brown 5–7 months after pollination. The seeds are black, 3–4 mm long, with a slender, 12–18 mm long pale brown wing.〔〔 ''Picea breweriana'' grows very slowly, typically less than per year. It occurs mainly on ridgetop sites with very heavy winter snow to provide a steady source of meltwater through the spring, but dry in the summer. The harsh ridgetop conditions minimize competition from other much faster-growing trees like Douglas-fir. It is very well adapted to cope with heavy snow and ice loads, with tough branches, and the drooping branchlets shedding snow readily.〔〔〔Frank Lang's Nature Notes: (US Forest Service ecology and the naming )〕 Outside its native range, ''P. breweriana'' is a highly valued ornamental tree in gardens, particularly in Great Britain and Scandinavia, where it is appreciated for its dramatically pendulous foliage.〔 This plant has gained the Royal Horticultural Society's Award of Garden Merit.〔(【引用サイトリンク】url=http://apps.rhs.org.uk/plantselector/plant?plantid=1460 )〕 File:Picea breweriana foliage.JPG|Foliage of a young tree, Ridge above Bear Lake, Ca. File:Picea breweriana - weeping twigs2.jpg|The weeping twigs File:Picea breweriana2.jpg|Foliage File:Picea breweriana leaf1.jpg|Close-up foliage File:Picea breweriana (flowers).jpg|Flowering File:Picea breweriana cones01.jpg|Young cone File:Picea breweriana mature cone.jpg|Mature cone ==References== 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「Picea breweriana」の詳細全文を読む スポンサード リンク
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