600 DR. M. ©. MASTERS: GENERAL VIEW 
sheath of stereome-cells. For the most part they are median, 
but occasionally peripheral. The cells of the mesophyll have 
infolded walls. The endoderm-cells (about 54 in number) are 
much thickened. The stomata are distributed on all sides of 
the leaf. 
41. Pixus Donyeii-Suitatt, Masters, in Botanical Gazette, 
xvi. (1891) p. 199 (Pirus), e¢ xix. (1894) p. 18, t. 2. 
This species was found by Mr. Godman, and subsequently by 
Capt. Donnell-Smith. It forms a complete belt around the 
Volean de Fuego, commencing at about 10,000 feet, and in 
the Volean d’Agua extends to the summit. It is curious to see, 
writes Mr. Godman, how abruptly the mixed forest of Chezro- 
stemon and other trees ceases at about 10,000 feet, and how you 
step suddenly out of it into the more open pine-belt, where the 
only undergrowth is a coarse grass (Godman in litt.). 
Capt. Donnell-Smith furnishes similar information, and states 
that he collected his specimens at the very top of the Volcan 
d’Agua, at a height of 12,300 ft., along the crest of the extinct 
volcano, where it formed a stunted tree 10-15 ft. high, but well 
furnished with cones. 
P. Donnell-Smithii resembles P. Hartwegi, but differs in its 
smaller cone-scales with less prominent apophyses. It is a 
5-leaved species with fimbriate bud-scales and three-sided leaves. 
The hypoderm is well marked, and there are also wedge-shaped 
masses of stereome-cells to add to the rigidity of the leaf. The 
cells of the leaf-cortex are sinuous, and the two branches of the 
fibro-vascular strand are separated by stereome-cells. The sec- 
tion of the meristele is triangular in outline. The resin-canals 
appear to be absent (see Pl. 21. fig.5). The cones are about 
lu cent. long, oblong-obtuse, thick, the scales with thickened 
apophyses and winged seeds. 
42. P. Hartwear, Lindley, Bot. Reg. (1839); Parlatore, in 
DC. Prod. xvi? p. 399. 
A Mexican species apparently very variable, and confused in 
collections with P. Montezuma. Like other mountain species 
from Mexico, it needs careful study on the spot. 
43. P. Montezuma”, Lambert; Parlatore, in DC. Prod. xvi’ 
p. 398 ; Gard. Chron., Oct. 25, 1890, March 3, 1894, March 11, 
1899, cum ie. 
A Mexican species so variable that no fewer than 70 synonyms 
