Picea 1 38 1 



about ^ in. long, incurved, ending in a rounded or acute (not acuminate) cartilaginous 

 tip ; quadrangular in section, with three to four rows of stomata on each side. 



Cones, deciduous in the autumn or winter of the first year after the escape of the 

 seeds, sessile or shortly stalked ; slender, cylindrical but tapering at both ends, about 

 2 in. long and ^ in. in diameter, green when growing, shining pale brown when ripe : 

 scales few, loosely imbricated, thin and flexible, so that the cone can be easily crushed 

 by the hand, orbicular or oval, ^ in. broad, rounded or truncate at the entire anterior 

 margin : bract about ^ in. long, oblong with a slightly enlarged ovate denticulate 

 lamina. Seed, ^ in. long, brown, partly embraced by the inflexed margins of the 

 base of the narrow pale wing, which is broadest near the rounded denticulate apex ; 

 seed with wing, f in. long. 



The three American species are often confused, though they have been clearly 

 recognised by botanists in Europe since Lambert's time. In America the younger 

 Michaux and Asa Gray united P. rubra with P. nigra ; but all modern American 

 botanists and foresters keep the three species distinct. The best account of 

 their history is given by Dr. G. Lawson of Halifax, Nova Scotia, in Proc. 

 Canad. Institute, 1887, pp. 169-179. Formerly the white spruce was considered 

 to be a native of the Rocky Mountains, but the tree inhabiting Alberta, British 

 Columbia, and Montana is now considered to be distinct, and has been named 

 P. albertiana. 



P. alba is readily distinguished by its bluish disagreeably smelling foliage and 

 glabrous branchlets, and cannot be confused with P. nigra and P. rubra, which have 

 pubescent branchlets and peculiar buds with long subulate scales. The cones of the 

 white spruce are easily crushed by the hand on account of their thin flexible scales, 

 and are very different in shape from those of the other two species, which have firm 

 rigid scales.^ 



Varieties 



1. Var. arctica, Kurz, in Bot. Jahrb. xix. 425 (1895). 



Abies arctica, Murray, mjourn. Bot. v. 253, t. 69 (1867). 



Finus alba, var. arctica, Parlatore, in De Candolle, Frod. xvi. 2, p. 414 (1868). 



Towards the northern limit of its area the white spruce has thicker leaves and 

 smaller cones, with more concave scales and bracts slightly different in shape. This 

 form was first collected by Seemann in north-western Alaska. According to Sargent ^ 

 the branchlets of the white spruce in the interior of Alaska are sometimes slightly 

 pubescent, and in all probability this variety is a connecting link between P. alba and 

 P. albertiana. 



A few peculiar forms have arisen in cultivation : — 



2. Var. nana, Loudon. A round compact bush, rarely exceeding 6 ft. in height. 



3. Beissner mentions fastigiate, pendulous, and variegated forms, which we have 

 not seen in England. 



1 Trelease. in Bot. Gaz. xxix. 196 (1900) describes remarkable burrs, almost globose in shape and covered with smooth 

 bark, which are occasionally seen on the trunk and branches of the white spruce m.the United States. 



2 Silva iV. Ar>u!r. xii. 38, note (1898). 



