AND GENERA OF PLANTS. 418 
Senecio * Schweinitzianus; 2, smooth, stem grooved; lower and radical leaves 
long petiolate, cordate, obtuse, or acutely cordate-ovate, coarsely or sharply 
toothed, incise at base; cauline pinnatifid, auriculate and amplexicaule, the 
auricle deeply cleft; umbell loose and subcompound; pedicels very long and 
mostly naked; a few minute bractes under the base of the involucrum ; in- 
volucrum smooth, the sepals acuminate, about twenty; rays about twelve, 
longer than the disk; achenium smooth; pappus nearly as long as the florets. 
Has. In Arkansa, and, according to Schweinitz, in Carolina, marked 8S. Caroliniana in his 
herbarium, but not, apparently, the plant of Sprengel. About a foot anda half high, p verfectly 
except a slight down, in the axills of the radical leaves. Radical leaves with the petioles four or 
five inches long, the lamina of the leaf two to three inches long, by one and a half to two broad; 
umbell compound, with as many as twenty capituli. 
_2 Senecio * Plattensis; 2, somewhat pubescent; base of the stem arachnoidly 
“tomentose; leaves all pinnatifid, the radical petiolate, cauline amplexicaule, - 
lobes oblong, denticulate, the centre lobe sublanceolate; corymb nearly simple; 
involucrum subcampanulate, minutely bracteolate ; sepals about twenty, acute; 
rays usually twelve, oblong, a little longer than the short involucrum; ache- 
nium puberulous; pappus about the length of the florets. 
Has. In the Rocky Mountain range, and in Arkansa. About ten to fourteen inches high; stem 
simple, striated. Corymb nearly simple, with ten to twelve heads of flowers, pedicels one to two 
inches long, slightly bracteolate. The Arkansa specimen is taller and more slender, with the 
primary small radical leaves entire and smooth, the leaves more elongated, and less denticulate. 
The whole habit of the plant, as well as the flowers, are very similar to S. tomentosus, at least the 
smoother variety, bas. ie achenium is less pubescent. 
Senecio micas: ©, smooth, dichotomously branched from the base; 
leaves all pinnatifid, auriculately amplexicaule; the rachis wide, with few acute ° 
segments, segments of the upper leaves denticulate; branches few-flowered, 
fastigiate, pedicels elongated, naked, the stmmit beneath the campanulate in- 
volucrum minutely bracteolate; sepals about twenty, smooth and carinated, 
with acute, reflected, sphacelous tips; rays about. fifteen, oblong, longer than 
the involucrum; achenium cylindric, ten-ribbed, the ribs strigose ; pappus about 
the length of the florets. . 
Has. In Upper California, near St. Barbara. Flowering in May. A very distinct species, 
allied, though remotely, to S. Californicus. The capituli, though fastigiate, are not in a corymb, 
but terminate the forked branchlets. Flowers bright yellow. Stem much — six to eight 
VIL-O D 
