"2 
OF THE GENUS PINUS. 605 
three sides, dorsum convex, lateral faces concave. Stomata are 
seen on all surfaces. Toere is a layer of thin-walled cells 
between the epidermis and the hypodermis, which latter is thick 
and strengthened at the corners. The cells of the mesophyll 
have infolded walls ; the resin-canals, when present, are in juxta- 
position to the elliptic meristele (as seen in section), and are 
surrounded by stereome-cells. The endoderm-cells are about 50 
in number, oblong, thickened on the outer side. The fibro- 
vascular bundle is double, a band of stereome-cells connecting 
the bases of the two phloem masses. The male flowers are 
capitate-corymbose, ascending, linear-oblong, 6-8 cent. long. 
The cones are shortly stalked, elongate-conic, slightly curved. 
The apophysis is convex on both sides of the umbo. Cotyledons 
7-10. 
An interesting account of this tree, showing its value for resin 
and timber, is to be seen in an article by Karl Mohr in ‘ Garden 
and Forest’ (1858), p. 261. Maurice de Vilmorin, in the same 
Journal, March 24, 1897, speaks of the tree as growing in 
Western France; and even at Kew a tall specimen braves the 
untoward cenditions in which it is placed. 
51. Prxus pseuposrrosus, Lindiey (1839); Parlatore, in DC. 
Prod. xvi? p. 401. 
A five-leaved Mexican species growing at elevations of 8000- 
10,000 feet. The leaves are three-sided, provided with hypoderm. 
The mesophyll-cells have infolded walls, and the resin-canals are 
adjacent to the angles of the triangular meristele, and each is 
surrounded by a sheath of stereome-cells. The fibro-vascular 
bundle is undivided. The cones are about 10-15 cent. long, ovoid- 
acute, or oblong conic; the apophysis convex, rugose, with the 
upper edge semilunar or elliptic, rarely somewhat truncated ; 
umbo deltoid, short, reflexed, sometimes depressed. 
52. P. oocarpa, Schiede; Parlatore, in DC. Prod. xvi.’ p. 401 ; 
Palmer, in Contrib. U.S. Nat. Herbarium Dep. of Agriculture, I. 
No. iv. June 30 (1891), p- 115. 
This tree is described as abundant in the mountains of Mexico, 
where it attains a height of 40-50 ft., with an ample, spreading 
head and rather pendulous branches. The leaves are in fives. 
Dr. Palmer (J. c.) says that “on each side of the leaf are two 
ducts which, with the surrounding strengthening cells, completely 
separate the parenchyma tissue into distinct regions ; the ducts 
