Picea 1385 



PICEA ALBERTIANA, Alberta White Spruce 



Picea alberHana, Stewardson Brown, in Torreya, vii. 126 (1907); Rehder, in Mitt. Deut. Dend. Ges., 



1907, p. 69; Britton and Shafer, M Amer. Trees, 58 (1908). 

 Picea Columbiana, Rydberg, in Mem. New York Bot. Garden, i. 11 (1900) (not Lemmon i) ; M. E. 



Jones, in Montana Botany Notes, 10 (1910). 

 Picea alba, Mayr, Fremdldnd. Wald- u. Parkbdume, 319 (in part), fig. 10 1 (1906) (not Link). 



A tree, attaining in western North America 160 feet in height. Bark thin, 

 greyish white, scaling off in small quadrangular plates, furrowed at the base of old 

 trunks. Young branchlets greyish or light yellow ; yellow or orange in the second 

 year ; glabrous or more usually with a minute pubescence on the pegs (from which 

 the leaves arise), which is occasionally scattered over the rest of the surface of the 

 pulvini. Buds about \ in. long, ovoid, slightly resinous, with scarious scales rounded 

 and entire in margin ; terminal buds girt at the base with acuminate ciliate keeled 

 scales. Leaves bluish green, in an imperfect radial arrangement on the lateral 

 branches, but more crowded on the upper side of the branchlets ; ^ to i in. long, soft 

 or rigid, curved, ending in a short point, quadrangular in section, with three to five 

 stomatic lines on each side. 



Cones, I to 2\ in. long, cylindrical, obtuse at the apex, sessile, about i in. wide 

 when open, shining light brown when ripe : scales numerous, thin, and flexible, fan- 

 shaped, wide, and rounded anteriorly, cuneate on the sides, flatter than those of P. 

 alba ; upper margin thin, undulate, or faintly denticulate ; light brown and glabrous 

 on the exposed part, minutely pubescent and reddish brown on the concealed part : 

 bract \ in. long, with an oblong claw, slightly expanded into a denticulate lamina, 

 which is either emarginate or rounded at the apex. Seed \ in. long, mottled dark 

 brown ; seed with wing \ in. long; wing contracted just above the seed, widest in the 

 upper two-thirds, ending in an oblique denticulate apex. 



This species is very variable in the amount of pubescence on the branchlets, 

 which is occasionally absent both in specimens from Montana^ and from Alberta. 

 The cones are also variable in size, and in the faint denticulation of the margin of 

 the scale. It is most closely allied to P. alba, of which it may be considered 

 the Rocky Mountain form. In Z'. alba the branchlets are always perfectly 

 glabrous, with less prominent pulvini ; and the leaves are differently arranged in 

 the two species. The buds of P. alba are non-resinous, with scales emarginate 

 or two-lobed, and not entire as in P. albertiana. The cones of P. alba are less 

 rigid, being easily crushed by the hand, and have very fragile scales, entire in margin, 

 more concave internally from side to side, and more reddish brown in colour than 

 those of P. albertiana. The seeds are similar in the two species, but those of 

 P. alba have shorter wings. 



> p. Columbiana, Lemmon, is imperfectly described, and is referred by Sargent and by Britton to P. Engelmanni. 

 Lemmon's description may have partly included P. alberHana ; but the latter name, being quite certain, must stand for the 

 species now treated here. Cf. p. 1388. 



» Three trees growing together in a clump at 3300 ft. altitude, near Belton in Montana, which I examined in 1906, were 

 precisely aUke in size, bark, and habit. One had perfectly glabrous branchlets, silvery leaves, and large cones. Another had 

 very pubescent branchlets, green leaves, and small cones. The third was intermediate. 



