180 CONTRIBUTIONS FROM THE NATIONAL HERBARIUM. 
connection. Stylopodium wanting. Oil tubes very small, 4 to 8 in 
the intervals (solitary in (. globosus), 8 to 14 on the commissural side 
(2 in C. globosus). Seed very flat, with plane face. 
Dwarf acaulescent xerophytie plants, with small pinnate or bipin- 
nate leaves, no involucre (except occasionally in @. fendleri and 
C. newberry?), usually foliaceous and conspicuous involucels, and white 
or vellow flowers. 
Type species, Se/énum acaule Pursh, Fl 2:Suppl. 732. 1814. 
A genus of 7 species belonging to the arid regions of western United 
States, a single species extending into Canada, 
The type of the genus is C. acauwlis (Selinuwim acaule Pursh), but eventually it was 
made to include an aggregate of species very different from this type. In our 
Revision the genus Coloptera was established to include forms that could not be asso- 
ciated with Cymopterus as generally understood. Later Mr. Marcus E. Jones called 
attention to the fact that certain species retained in Cymopterus had the essential 
Fig. 53.—Cymopterus parryi: a, * 6; b, « 8. 
characters of Coloptera, and a reexamination of old and new material has led us to 
the discovery that Coloptera represents the real genus Cyimopteru3 as established by 
Rafinesque. Accordingly, the species of Coloptera and certain species of Cymopterus 
are herein set apart under the genus Cymopterus as established, and the other species 
of Cymopterus, those which have been commonly taken to represent the genus, are 
otherwise disposed of. 
The genus, as here set forth, appears to be a very natural one. The forms all 
appear acaulescent, so faras the aerial habit is concerned, the cluster of leaves and 
flowering stems forming a rosette which seems to be usually prostrate. Beneath the 
surface the rosette arises from aslender stem which is more or less elongated, depend- 
ent upon the depth of the elongated and thick root. The whole structure is strongly 
xerophytic, the plants growing in dry, sandy, or gravelly soil. 
The species are also remarkably restricted in range, being confined to the arid 
regions of New Mexico, Arizona, Colorado, Utah, and Nevada, with the single 
exception of C. acaulis, the type of the genus, which has an extensive northern and 
eastern range. 
The ‘leaf habit is quite uniform, the blades being in various states of pinnate 
division between simply pinnate and almost thrice pinnate, so that such terms as 
leaf 
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