594 DR. M. T. MASTERS: GENERAL VIEW 
by Douglas, in 1826; but it was not till 1836 that the name 
ponderosa was published in the ‘Companion’ to the Botanical 
Magazine, ii. p. 111, where Douglas says:—“ I also saw a new 
Pine (Pinus ponderosa).” This was on the hills between 
Colombia and Spokan rivers. 
For an account of the numerous varieties reference may be 
made to Sargent’s work, p. 80. Some of them, like P. Jeffrey?, 
latifolia, Engelmannit of Lemmon, Mayriana of Sudworth, 
Apacheca of Lemmon, scopulorum, Lemmon, have been con- 
sidered to be worthy of specific rank, but Sargent concludes 
that the forms mingle so as to be indistinguishable. 
In the ‘Silva’ figures are given not only of the type but of the 
var. Jeffreyi, tab. 563, and var. scopulorum, tab. 564. 
P. Jeffreyi is also discussed by Sargent in ‘Garden and 
Forest,’ Sept. 30, 1891, p. 457, and a good figure is given in the 
‘Gardeners’ Chronicle, March 23, 1889, p. 360. It was the 
subject of an interesting note by Sir Joseph Hooker in the same 
periodical, Dec. 27, 1884, p. 814. 
In the germinating seedling the radicle is tapering, the caulicle 
is cylindric, glaucous. 
The cotyledons are 10 in number, but from 6-11 are recorded, 
triangular in section, with lines of stomata on the two lateral 
faces. 
In the three-sided leaves there is often a layer of water-cells 
beneath the epidermis and a double layer of hypoderm. The walls 
in the cells of the leaf-cortex are sinuous, the resin-canals paren- 
chymatous. The meristele is oval, or slightly triangular in 
outline, and surrounded by the endoderm-layer of 50-60 cells, 
thickened on the outer faces. The fibro-vascular strand is 
divided, the two divisions being separated by stereome-cells. 
P. Jeffreyi has essentially the same structure, but Coulter and 
Rose remark that the thin-walled subepidermal layer is wanting 
in Jeffreyi, but then it is not constant in ponderosa! 
The male flowers are 12-15 mill. long, sometimes twisted, each 
surrounded by about 10 scales. 
32. Pinus arrenvata, Lemmon (1892); Sargent, Silva, xi- 
(1897) p. 107.—P. tuberculata, Gordon ; Masters, in Gard. Chron. 
Dec. 19, 1885, fig. 184. 
This is the species usually known as P. tuberculata of Gordon 
(1849) (not of D. Don (1886), which is = P. radiata). 
It grows on the sun-burnt slopes of the mountains of Oregon, 
