95 8 The Trees of Great Britain and Ireland 



at Grayswood, Haslemere, planted in 1888, is now about 30 feet in height and i foot 

 8 inches in girth. 



According to De Wildeman, var. occidentalis was introduced from British 

 Columbia in 1891, by Dieck and Purpus, into the arboretum at Zoschen. 



ALNUS RHOMBIFOLIA 



Alnus rhombifolia, Nuttall, Sylva, i. 33 (1842); Sargent, Silva N. Amer. ix. 77, t. 456 (1896), and 



Trees N. Amer. 212 (1905); Winkler, BetulacecB, 115 (1904). 

 Alnus oblongifolia, Watson, in Brewer and Watson, Bot. Calif, ii. 80 (1880) (in part). 



A tree attaining 80 feet in height and 9 feet in girth. Young branchlets 

 pubescent. Leaves (Plate 268, Fig. 13) on young trees up to 5 inches long and 

 3 inches broad, on old trees 3 inches long and i^ inch broad, ovate or oval, rounded 

 and unequal at the base, acute or rounded at the apex ; margin slightly thickened and 

 reflexed, finely and irregularly serrate, and ciliate ; nerves, ten or eleven pairs, 

 running parallel and slightly curved to the margin ; upper surface dark green, 

 shining, glabrous ; lower surface light green, pubescent, the pubescence strongest 

 on the midrib and nerves ; petiole, ^ inch, pubescent. Buds stalked, pubescent. 

 Staminate catkins, in pubescent racemes, deciduous before the opening of the 

 leaves ; stamens, two or three, rarely one. Cones oblong, 5 to ^ inch long, fully 

 grown at midsummer, but remaining closed till the trees flower in the following 

 year ; nutlet broadly ovate with a thin, acute margin. 



This species grows on the banks of streams from northern Idaho to the eastern 

 slope of the Cascade Mountains in Washington and Oregon, extending southward 

 over the coast ranges and along the western slopes of the Sierra Nevada to the 

 mountains of southern California. It is the common alder of central California, and 

 the only species at low altitudes in the southern part of this state. 



It is extremely rare in cultivation, the only specimen which we have seen 

 being a small plant in Lord Aldenham's remarkable collection of shrubs and trees 

 at Aldenham, Herts. According to Nicholson,^ it was introduced into cultivation 

 in 1888. 



1 Did. Gardening, Suppl. 34 (igoo). 



