Brewer Spruce

''Picea breweriana'', known as Brewer spruce, Brewer's weeping spruce, or weeping spruce, is a species of spruce native to western North America, where it is one of the rarest on the continent. The specific epithet ''breweriana'' is in honor of the American botanist William Henry Brewer.

Description

Brewer spruce is a large evergreen conifer growing to 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 up to , 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 millimetres long and very rough with pulvini 1–2 mm long.

The leaves are borne singly on the pulvini, and are needle-like (though not sharp), 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, 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.

Genome

DNA analysesRan, 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.

Distribution

It is endemic to the Klamath Mountains of southwest Oregon and northwest California, and grows at moderately high altitudes, from above sea level.Farjon, A. (1990). ''Pinaceae. Drawings and Descriptions of the Genera''. Koeltz Scientific Books .Rushforth, K. (1987). ''Conifers''. Helm .

Uses

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.

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, Fresh female cones
File:Picea breweriana cones01.jpg, Mature male cones & developing female cone
File:Picea breweriana mature cone.jpg, Mature cone

References

External links

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Catalogue of Life: ''Picea breweriana''


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breweriana
Flora of the Klamath Mountains
Endemic flora of the United States
Flora of California
Flora of Oregon
Trees of the Southwestern United States
Trees of the Northwestern United States
Endemic flora of Oregon