SEGREGATES OF CALTHA LEPTOSEPALA. 
During almost thirty years I have been acquiring famil- 
iarity in field and herbarium with the white-flowered Caltha 
species common in alpine or subalpine districts of our far- 
western mountains, from New Mexico to Montana and from 
middle California to Alaska, all of which have until now 
been referred partly to C. biflora and partly to C. leptosepala ; 
or else, as by all our botanists not long ago, even C. biflora 
itself, and all the rest were called forms of C. leptosepala. 
The species last named was founded on specimens derived 
from the seaboard of subaretie North America, a country as 
different climatologically and phytologically as Iceland is 
different from the mountain districts of Italy and Spain. 
I have never yet had the good fortune to visit those high- 
northern shores which are the habitat of the genuine C. lep- 
tosepala, and so have never seen it growing; but it has for 
some years been evident to me, from the herbarium speci- 
mens, that nothing answering to the diagnosis of C. lep- 
tosepala is found within the limits of the United States, or 
even near our borders; forall our southerly and alpine speci- 
mens are most strictly acaulescent, their flowers, though 
numerous, all being solitary, terminating axillary scapes, 
whereas, in the far-northwestern plants each individual dis- 
plays but a single apparently terminal leaf-bearing stem 
with two flowers, one of which is properly terminal, the other 
axillary to the solitary leaf. Moreover, while the far-northern 
plants exhibit filiform filaments, our mountain species, at 
least some of them, have short and more or less flattened 
filaments. When one has detected such strong differential 
characters as these which I have thus indicated, it is no 
longer possible to regard all these things as variations of 
Prrronta, Vol. IV. Pages 73-101. 8 Dec., 1899. 
