510 



DR. MAXWELL T. MASTERS ON 



Fig. 10. 



Menziesii of North-west America, from which it differs in its 

 natter, less deeply keeled, and blunter leaves. In the American 

 species, moreover, there are usually no resin-eanals. In culti- 

 vation the habit and general aspect of the two trees are different ; 

 but upon this point very little, if indeed any, reliance can be 

 placed. Dr. Engelmann states {in litt.) that he has examined a 

 cone of the typical P. sitkensis, in which he found the bracts to 

 be lanceolate, remarkably large, half as long as the scarcely un- 

 dulate scale, while in P. ajanensis the bracts are minute, short 

 and oval, and the scales are undulate. Maximowicz also describes 

 the bracts of P. ajanensis as minute, suborbicular (Primit. Fl. 

 Amur.). Maximowicz further indicates two varieties of P. aja- 

 nensis — var. a. genuina, with cone-scales markedly denticulate ; 

 the other, var. ft, with cone-scales subentire. 



"With reference to the position of the resin-canals, they appear 

 to be on the upper surface of the leaves, and therefore different 

 in that respect from the leaves of many 

 other Conifers. In describing the species in 



the ' Gardeners' Chronicle,' as also in the 



mention made of it in the ' Journal ' of this 



Society, vol. xvii. p. 549, I fell into the error 



of describing the upper surface as dark 



green, the lower surface as glaucous. This 



is, indeed, apparently true of the lateral 



shoots ; but the real disposition is exactly 



the reverse. In order to avoid further con- 

 fusion, I would here call attention to the 



leaves on the erect leader-shoots and to 



those on the side-branches respectively. On 



the erect shoots the leaves are not twisted 



at the base, but are erect and appressed to 



the stem, the glaucous surface being next 



the axis, somewhat concave and abundantly 



provided with stomata ; the midrib is con- 

 tinued throughout the whole length of this 



surface, and may be excurrent into a " mu- 



cro " (fig. 11). The green convex surface is 



external, marked with three ridges, and in 



the furrows between the central larger and 



the lateral smaller ridges are placed the resin- Portion of shoot and 



canals. It terminates in a flat rhomboidal Picea ajanensi*. 



