es 
AND GENERA OF PLANTS. 361 
_ Has. Georgia. (Dr. Baldwyn.) A small species, about a foot high, with long, narrow, linear 
entire leaflets, sometimes with here and there a distant gash. Flower rather small, rays nearly Pes 
entire. 
§ 1. *MEDUSEX.— Outer involucrum. very. long and squarrose, of twenty to 
twenty-four leaves! the inner eight-leaved. Achentum ciliate, terminated by- 
two very short teeth. 
Diodonta tnvolucrata. Coreopsis involucrata; Nutt. in Journ. Acad. Nat. 
Sci. Philad., Vol. VIL, p. 74. Very remarkable for the singular involucrum, 
which, while all the other parts of the plant are smooth, has its segments 
strongly ciliated with rigid hairs. I have not seen the mature achenium. 
§? 1. * HeTERODONTA. 
Bivens, but with the outer, foliaceous involucrum three to four-leaved, the 
* 
inner about six-leaved, elongated. Rays two or three, very short, not ex- 
serted. Stigma smooth, with a small conic point. Achenium linear, flatly 
compressed, without angles at the sides or summit, hirsute, immarginate. 
Pappus of two long, diverging, hispid bristles, with the hairs erect, not re- 
trorse! radial, abortive fruit, with very short awns.—A dwarf, much branched 
annual? with opposite, lanceolate-linear, incisely serrated leaves, attenuated 
at each extremity. Flowers solitary, terminal; scales of the involucrum 
yellowish. Discal florets shorter than the awns, campanulate with a very 
slender tube. —(The name in allusion to the erect, instead of reverted bris- 
tles of the teeth of the achenium. ) 
Diodonta * Bidentoides. ai; , 
Has. The vicinity of Philadelphia? With entirely the aspect of the dwarf variety of Bidens 
cernua, but with the capitulum almost obconic-oblong. Height two or three inches, spreading out 
five or six inches; leaves attenuated into long petioles, somewhat connate at base. 
A second species of this section, or rather genus, occurs in the south-west, and will be described 
by Mr. Gray. 
*COSMIDIUM. (§. Cosmrpium of Coreopsis, Gray.) 
Coreopsis, but with the discal florets long, tubular and campanulate, deeply 
five-cleft. Achenium subcylindric, usually tubercular and indurated, with 
vVil.—4 Q 
