4 Rhodora : [JANUARY 
of the oblique rib connecting the intermediate ribs at apex with the 
main ribs of the calyx, which itself (i. e. the cross-rib) is also always 
hairy; while each of the twenty-two collections from western America, 
including the area from Kotzebue Sound to Monterey, is absolutely 
glabrous between the ribs, although these are frequently as hairy as 
in the eastern species, and the cross-ribs uniting the main and inter- 
mediate ribs are likewise always perfectly glabrous. Although no 
other constant differences have been discovered between the plants 
of the two areas, the absolute constancy of this feature and its correla- 
tion with geographic distribution, in the light of the importance laid 
upon just this character by Wallroth and Boissier, lead me to consider 
the plants perfectly distinct. The two western species of the Pleuro- 
trichae proposed by Wallroth, however, are not confirmed by the 
material examined, which is much more extensive than that accessible 
to him. 
Although agreeing in the essential character of pubescence of the 
calyx-limb, the eastern plants differ somewhat among themselves in 
regard to the shape of the calyx-lobes, which may be merely acuminate, 
apiculate, short-cuspidate, or rather long-cuspidate (cusp 0.4-0.5 mm. 
long). Careful study shows that while the distinction between the 
long-cuspidate and short-cuspidate forms seems a fairly constant one, 
no line can be drawn between the short-cuspidate, apiculate, and 
acuminate forms, all three or gradations between them occurring not 
rarely on the same calyx. Accordingly it has seemed best to recog- 
nize the long-cuspidate form, which best agrees with Wallroth’s 
description of his A. labradorica, as varietally distinct from the more 
varied but entirely intergradient plexus of short-cuspidate to acumi- 
nate forms. While the long-cuspidate form, in all the material 
at hand, is always pubescent on the scape, as described by Wallroth, 
the other plant occurs in both a glabrous and a pubescent form, 
although no concomitant characters have been found to distinguish 
them. It has seemed advisable to give this variation only formal 
recognition. The three sheets of this variety with merely acumi- 
nate or apiculate calyx-lobes from Mount Albert, Quebec, the only 
known station south of Labrador, agree in having ciliate leaves, all 
the others being glabrous on the leaves even if puberulous on the 
scapes, with the exception of a single collection from Labrador. 
The western plants, as has been brought to my attention by Prof. 
Fernald, also show differences among themselves worthy of at least 
