RYDBERG: Rocky MounrTAIN FLORA 457 
Achillea Millefolium. It is characterized by the small rays, 
only 1.5-2.5 mm. broad, and straw-colored bracts, pointed out 
by Pollard. It differs also from A. Millefolium in the narrow 
linear and usually more elongated segments of the leaves. There 
is also only a trace of a wing-margin on the rachis and the stem 
is usually more hairy and with longer hairs. DeCandolle regarded 
it as a variety of A. Millefolium and stated that it is intermediate 
between that species and A. setacea, a native of Southern Europe. 
In my opinion it is nearer to A. setacea, having the small rays 
and narrow segments of that species, but is more hairy. It is the 
common native form of the prairie region from Wisconsin to Ken- 
tucky, Arkansas, and eastern Nebraska, but specimens have 
been collected as far east as Pennsylvania and South Carolina. 
ree sp from southern Colorado I have also referred here. 
PCL TIS 
ACHILLEA LANULOSA Nutt. Journ. Acad. Nat. Sci. Philadelphia 7: 
36. 1834 
A. tomentosa Pursh, Fl. Am. Sept. 561. 1814. Not A. tomen- 
tosa L. 1753. 
This resembles the foregoing in many respects; the pubescence 
(although often more copious) and the color of the bracts are 
the same. The segments of the leaves are much shorter and more 
crowded and more directed forward; the rachis has not even a 
trace of a wing margin and the rays are much larger, 2.5-4 mm. 
(Pollard gives them up to 6 mm.) broad. This is the common 
plant of the Rocky Mountain region and its range extends from 
Saskatchewan to Kansas, New Mexico, northern Mexico, the 
mountains of California, and British Columbia. 
ACHILLEA SUBALPINA Greene, Leaflets 1: 145. 1905 
A. lanulosa alpicola Rydb. Mem. N. Y. Bot. Gard. 1: 426. 1900. 
A. alpicola Rydb. Bull. Torrey Club 33: 157. 1906. 
This resembles a depauperate Achillea lanulosa in habit, but 
the margins of the bracts are strongly colored, usually almost 
black, though sometimes only brown, and such specimens ap- 
proach closely A. lanulosa. The inner bracts as are a rule de- 
cidedly acute and in this respect it resembles A. borealis. It 
differs, however, from that species in the small heads, not over 4 
