The Species of the Genus Larix. 21 
basis of PRATT's discovery (Journ. Linn. Soc. Bot. XXVI. 
1902, p. 558; Engl. Bot. Jahrb. XLVIII, 1913 p. 746). 
FRANCHET, however (Journ. de Bot. XIII, 1899, p. 262), cor- 
rectly identified PRATT’s discovery with L. tibetica (= L. 
Potanini Bat.). 
The distinguishing characteristics of L. Potanini from L. 
Griffithiana and L. Mastersiana are best demonstrated by 
an examination of the cones. In the case of the former, 
the bracts of the mature cone are not more than 2 mms. 
longer than the cone-scales, and are straight, while, in the 
case of the other two latter species, they are relatively 
longer, and strongly reflexed. The cone is violet with red 
bracts, that of L. Mastersiana being brown with red bracts. 
The first-year’s shoots are of a deep reddish-brown 
colour (Wırson, No. 903), or orange-brown (WILSON, 
No. 910), with prominent, lighter-coloured stigmata. The 
leaves are placed in bundles of up to fifty on the dwarf 
branchlets, 1,5—3 cms. in length, and are similar to L. 
Mastersiana in being distinctly keeled on the under-side, 
the keel on the upper-side being only noticeable at the base. 
All three south-asiatic larches (L. Griffithiana, L. Master- 
siana and L. Potanini) have a prominent keel on the under- 
side of the leaf, and are also partly keeled on the upper- 
side; but none of them can be compared to L. Lyallii, the 
leaves of which are prominently keeled on both sides. 
The leaves of L. Potanini have been described as four- 
sided when seen in tranverse section, being keeled on the 
upper as well as the under-side (DALLIMORE & JACKSON: 
Handb. Conif. 1923, p. 297); but we have been unable to 
observe this dissimilarity from L. Mastersiana and L. Griffi- 
thiana in the specimens we have examined. 
In the localities where the tree altains its best growth, 
