CALLISTERIS. ; 159 
A Proposed New Genus, Callisteris. 
An early attempt to resolve into natural genera the confused 
and impossible “ Gilia ” of Bentham and of Asa Gray, has been 
for years interrupted ; but I here offer one of the ideas long 
entertained, namely the segregation of a natural group, all 
biennials or perennials, and of peculiar habit, of which Pursch’s 
Cantua aggregata is typical. From the /pomopsis of Michaux, 
itself an excellent genus and monotypic, they differ not only 
habitally and in foliage, but widely in character of calyx and 
seeds. They are in technical character, far nearer true Gila, 
differing therefrom mainly by peculiar habit, biennial or peren- 
nial root, more fleshy and pectinate-pinnate foliage, a corolla of 
characteristic configuration and almost always in a manner 
bilabiate, the segments not radiating regularly, but one-sidedly 
to a greater or less degree. Moreover, no Gita makes any 
approach to these plants in the peculiarity of their thyrsoid 
panicled, or really thyrsoid inflorescence. I recognize following 
geographic species of the genus CALLISTERIS: 
C. AGGREGATA. Cantua aggregata, Pursch, Fl. i, 147. Calyx- 
teeth greatly exceeding the short tube, triangular-subulate, 
slenderly attenuate, herbaceous except laterally near base, 
hardly spinescent: corolla with rather short lobes very acute. 
Plains and foothills of the Rocky Mountain region eastward 
and northward. 
C. COLLINA. Calyx-teeth not half as long as the almost cyl- 
indric tubes, very obtuse, abruptly aristate-pointed, the point 
straight, rigidly erect: corolla only pinkish, its oblong-lanceo- 
late very acute lobes reflexed, and irregularly so. 
Bluffs of Clear Creek on the plains not far from Denver, 
collected by myself, July, 1870. Typein my own herbarium. 
C. LEUCANTHA. Two feet high, stout, the copious thyrsus of 
large white flowers a foot long; calyx subcylindric, purple, its 
lobes obtuse but each ending in short herbaceous. recurved 
tip: lobes of the very long corolla rather wide, oblong, hardly 
acute. 
At elevations of 8,000 and 9,000 feet in the Colorado moun- 
