588 DR. M. T. MASTERS: GENERAL VIEW 
closely allied, in its shorter, thicker leaves which bear stomata on 
the dorsal side. It is, indeed, so near to Pinus cembroides that 
I should have included it under that species, but that those who 
have had the opportunity of seeing both species in their native 
localities keep them distinct. Newberry and Meehan, in the 
‘ Bulletin of the Torrey Botanical Club’ (1885), vol. xii. pp. 50, 
81, consider P. monophylla (ante, p. 584) to be a dwarfed and 
depauperate form of P. edulis, but in this opinion I find it hard 
to concur. See Masters in ‘ Gardeners’ Chronicle’ (Nov. 5, 
1892) p. 563. 
The leaves are three-sided, with a thick hypoderm, mesophyll- 
cells plicated, marginal resin-canals, a circular meristele 
surrounded by an endoderm-layer of about 18-20 cells. The 
fibro-vascular bundle is unbranched. The male inflorescence is 
subglobose or oblong, the individual flowers 5-7 mill. long, each 
protected by four bracts. Inthe young cone the apophysis is 
convex, with a prominent umbo. The cotyledons number from 
7-10. 
18. Pinus atBrcauits, Engelmann ; Sargent, Silva, xi. (1897) 
p- 39, t. 548. 
This species isa native of the Rocky Mountains, British 
Columbia, Oregon, and California as far south as the San 
Bernardino Mountains (Sargent). The leaves have dorsal 
stomata and a double layer of hypoderm, which affords protection 
in the exposed situations in which it grows. The resin-canals 
are marginal; the mesophyll-cells are plicated. The endoderm 
consists of about 30 cells, and the meristele is circular in section. 
The male flowers have 8-10 bracts at the base (Engelmann). 
The connective of the anther is revolute, laciniate or reduced to 
a simple point. 
Engelmann at one time considered it a form of P. flexilis, but 
this grows at lower elevations and in different districts. The 
male flowers of P. albicaulis, moreover, are thicker and rounder 
than in flerilis, and the cone-scales are thicker at the tips 
and more abruptly subulate-mucronate. Both have nearly 
wingless seeds. Sir Joseph Hooker, in the ‘Gardeners’ Chronicle,’ 
June 27, 1885, describes and figures the remarkable effect of the 
blasts of sand in scoring and polishing the exposed wood of 
this tree. 
en oo 
