370 DESCRIPTIONS OF NEW SPECIES 
nutely bidentate, those of the disk oblong, with two short teeth, and a mi- 
- pute intermediate, paleaceous crown; one or two central florets, with two 
minutely retrorse bristly awns as long as the floret. Branches of the style 
terminated by a small abrupt cone—A dwarf annual of Peru. Stem ap- 
parently simple; leaves ternate and opposite, trifid or three-lobed, ciliate. 
Flowers terminal, yellow. | : 
Microdonta * nana; ©. 
Has. Near Arequipa, Peru. (Mr. Curson.) The whole plant about two inches high. Stem 
simple, pilose above, terminating in a single flower. Leaves petiolate, the petiole and a line down 
the stem ciliate and pilose; the simple leaves oval, three to five-toothed, segments of the trifid leaves 
narrower, also three-toothed. Segments of the outer involucrum linear-oblong, distinct to the base, 
longer than the inner, hirsute. Inner involucrum, like that of Bidens, the segments nearly smooth, 
oblong-oval, many-nerved like the rays. Rays five, oblong, truncate, shortly three-toothed, about 
twice the length of the inner involucrum, many-nerved, with a rather long narrow tube, stigmas 
’ slender, not thickened at the extremity as in the discal florets, and nearly smooth. Discal florets, 
as well as the rays, yellow, subcampanulate above, the tube contracted rather more than a third the 
length of the upper part of the floret. Palea flat, very similar to the inner involucrum, and equally 
wide. The achenium of the ray largest and most perfect, elliptic, truneate, minutely bidentate, 
naked; those of the disk narrower, but not rostrate, with short, smooth teeth, and a row of minute, 
intermediate, slender, chaffy scales; one or rarely two, of the central florets producing the usual two 
awns of a Bidens, but scarcely as long as the achenium, and minutely barbellated with retrorse 
bristles. I have described from two specimens. The flower, rather large for the diminutive size 
of the plant. A remarkably distinct genus in the BiveNTIDER, the rays being more perfect than 
the discal florets, and without awns; the attenuation of the discal fruit above, without being pro- 
perly rostrate, would seem to ally our plant to Cosmos, from which, however, it is wholly distinct. 
Division V.—VERBESINEE. (Lessing.) 
§ 1. Leaves not decurrent. 
VERBESINA * villosa; herbaceous, stem terete, pubescent, leaves alternate, 
lanceolate, sessile, at both ends acuminate, entire or repandly denticulate, above 
scabrous, beneath softly villous; corymb compound; rays about three, (white;) 
sepals softly pubescent, linear, acuminate; achenium subpubescent, without 
winged margin. 
Has. Plains of Arkansa. Resembles V. virginica, though perfectly distinct, and much nearer 
to V. acuminata. A stout, tall plant; leaves half a foot long, two inches wide, cuneately narrowed 
below, upper part of the stem and peduncles densely villous; flowers clustered; achenium cuneate, 
without any sensible wing, the two awns slender and somewhat pilose. 
