376 DESCRIPTIONS OF NEW SPECIES 
: _ ¥*MACROCARPHUS. 
Hymenoparrvus, but with the leaves of the involucrum linear, numerous, 
(fifteen to twenty,) equal, in nearly a single series, and almost without mem- 
branaceous margins. Receptacle naked. Florets tubular, the shortly five- 
cleft border pubescent; the outer series somewhat ringent, but not spread- 
ing. Branches of the style hirsute, filiform, thicker towards the extremity. 
- Achenium linear, conic, subcylindric, villous, attenuated below; with a 
chaffy, nerveless pappus of about ten to twelve unequal, lacerated, oblong, 
obtuse leaflets more than half its length; the pappus of the outer florets 
shorter.—Biennial herbs of the north-west coast of America, and the Rocky 
Mountains, with tomentose, bipinnatifid, alternate leaves. Stems dichoto- 
mous, corymbose. Capitulum many-flowered, the florets rosaceous, or nearly 
white, with the tube of anthers exserted, their cusps linear and acute, the 
base naked.—Intermediate between Chenactis and Hymenopappus; differ- 
ing from the former in its nearly. equal florets, filiform, and not subulate 
stigma, nearly terete achenium, and a pappus of many long, obtuse leaflets ; 
from the latter in the narrow-leaved involucrum, long leaves of the pappus, 
and the form of the florets, which are merely tubular, not campanulate— 
(Named in allusion to the great length of the pappus.) | 
_ Macrocarphus Achilleefolius; canescently tomentose; branches corymbose, 
leaves bipinnatifid, lobes short, oblong-obtuse; sepals canescently tomentose, 
about twenty; chaff of the pappus nearly the length of the elongated, villous 
achenium. Chenactis Achilleefolia; Hoox. and Arn. Bot. Beech., 1. ¢. 
Has. In the Rocky Mountain range, on Ham’s Fork of the Colorado; common. Flowering in 
July and August. Capitulum large, the florets. pale rose-red. Robust, biennial, about four to six 
inches high; the leaflets and lobes crowded, as in Milfoil. 
Macrocarphus Douglasii; deciduously and slenderly tomentose; stem branch- 
ing, corymbose; leaves pinnatifid, lobes entire or subdivided, oblong, obtuse; 
sepals glandularly and minutely pubescent; radial achenium glandularly sca- 
brous, slightly pubescent, with a nearly equal pappus about half its length. 
