228 PITTONIA. ` 
Bay district, several of which are in the Canadian Survey 
collection in flower only, might be obtained in fruit. At 
present I dare not attempt a classification of the incomplete, 
though by no means scanty, material from those parts, as it 
exists in the great Canadian Herbarium referred to. 
From the far northwest the specimens are all more mature, 
and therefore more successfully dealt with; and from the 
number of new species which I am already able to define 
from not only the northern, but the middle Rocky Mountain 
regions, it seems that this long stretch of elevated country is 
the center of distribution for Taraxacum as indigenous to 
our continent. 
Y T. CHAMISSONIS, Glabrous throughout, or the scapes 
tomentose or villous under the involuere: leaves large, of 
obovate-oblong or broadly oblanceolate outline, obtuse, or 
mucronately or euspidately acute, and from lightly runci- 
nate-toothed to more deeply cut into triangular usually en- 
tire or sometimes saliently dentate lobes: scapes few, stout, 
erect, sometimes more than a foot long: involucres of a 
very dark green, the outer set of bracts in about 3 series, 
erect and imbricated, from broadly and deltoidly ovate to 
ovate-lanceolate, commonly abruptly apiculate, rarely some 
of the inner developing a horn; inner linear-lanceolate not 
rarely corniculate: achenes of a rather greenish brown, 
spinulose about the summit, the 3 or 4 angles smooth 
below the summit, the intervening ribs more or less dis- 
tinctly low-tuberculate; the beak twice or thrice the length 
of the achene. 
This is the most common Taraxacum of Alaskan and 
Bering Sea shores and islands. Its most constant pecu- 
liarity is that of a very dark-colored, almost blackish, in- 
volucre, of which the outer scales are very broad, strictly 
erect and imbricated. 
