and Old World Birches. 185 
BrTuLA MICROPHYLLA. 
Professor Sargent has recently referred* to the fact that the 
writer identifies the common brown-barked tree or half-shrub 
of the Rocky Mountains with Bunge’s Betula microphylla 
described from the Altai of central Asia. Professor Sargent, 
owever, was unwilling to identify the American tree with 
Bunge’s species, and he accordingly proposed for it the new 
name B. fontinalis. But a further. comparison of B. fon- 
tinalis and an autheutic branch from the Altai of Bunge’s 
species sent from the Imperial Herbarium of St. Petersburg 
to the Gray Herbarium, some of the original Tyan Shan mate- 
rial of Regel’s B. alba, subsp. soongoricat in the Gray Her- 
barium and in the United States National Herbarium, the 
figures of Regel’s B. fruticosa, var. cuneifolia,t and lastly 
the original detailed full-page description by Bunge of his 
B. microphylla,§ has more firmly convinced the writer that 
all three of these trees described from the Altai and the Tyan 
Shan ranges are one species, B. microphylla, Bunge; and that 
this species differs from B. rhombifolia, Nutt. (B. occidentalis, 
Nutt. and of many other authors, not Hook, B. fontinalis, 
Sargent) only in growing among the mountains of centrai 
Asia rather than among those of northwestern America. 
A comparison of Bunge’s original description of Betula 
microphylla with Nuttall’s description of his B. occidentalis, 
the tree subsequently called by Sargent B. fontinalis, shows 
no definite character of leaves, strobiles, samaras, nor twigs 
upon which the two may be separated; and Bunge’s words, 
“epidermide trunci flavescente neque alba, primo intuito dis- 
tinctissima,’"™| are certainly not inapplicable to the small tree of 
northwestern America described in the Botany of California 
“with close dark-colored bark (at length light brown).”** Fur- 
* Bot. Gaz. xxxi, 239. 
+ Bull. S at. vi—repr. Enun. Pl, Semenow. (1869) 99. 
{ Regel, Mon, Bet. (1861) 35. t. 7, figs. 16-23. 
$ St. Pé ém. Savans & ii (1835) 606—reprint, Fl. Alt. Suppl. 84. 
. Mém 
| Nutt., Sylva, i, 22, t. 7 ( ‘ *| Bunge, 1. e. 
Watson, Bot, Cal. ii, 79. t+ Nutt., 1. ¢. 24, t. 8. 
