AND GENERA OF PLANTS. 847 
é > pe Fes, ‘ 
Achenium oboval, compressed, but somewhat turgid.—Tall annuals with 
opposite, ovate, serrated leaves, hirsutely canescent beneath; the flowers in 
_ terminal, naked, spiked panicles; in the fertile plant the spikes are filiform 
and interrupted.—AImost intermediate with Ambrosia and Iva.—(The name 
from mmporys, bitterness; in allusion to the qualities of the plant.) 
Iva * paniculata. 
Has. In the Rocky Mountains, by streams, in alluvial wastes. A rather tall annual, with long, 
petiolated leaves; the stem simple, terminating in a naked, branching, pyramidal panicle of green- 
ish, inconspicuous flowers. Involucrum about five-leaved, obtuse; male capitulum about fifteen- 
flowered, with minute rudiments of female flowers; in the fertile capitulum the female flowers are 
about eight. 
Iva xanthafola; ©, ti lanceolate-ovate, serrate, acuminate, long petio- 
late, appressed pilose, and canescent beneath; capituli somewhat spiked; se- 
pals ovate, acuminate.—Nurr. Gen. Am., Vol. II., p. 185. Decanp., Vol. 
Y., p. 529. Nearly allied to the preceding. 
Division.—PARTHENIES. 
*BOLOPHYTA. 
Capituli many-flowered, heterogamous; rays feminine in one series, about five, 
ligulate, nearly tubular, very short, truncated and crenulate; radial florets 
tubular, five-toothed, masculine, with a simple stigma. Involucrum hemi- 
spherical, biserial, external scales ovate, a ‘suborbicular. Receptacle 
conic, paleaceous, the palea sheathing, wider and pubescent at the summits. 
Stigmas of the ray short, smooth and obtuse. Secinin compressed, some- 
what obcordate, with a cartilaginous margin, to which it is ingrafted on 
either side with the two anterior palee, and with which, and the contiguous 
scale of the involucrum, it is at length deciduous. Pappus none, the ache- 
nium crowned with the small, persisting ligula.—An alpine, cespitose, stem- 
less, small perennial, with a long, almost ligneous root, crowned with dense 
and numerous vestiges of former leaves, based by tufts of hairs; leaves spathu- 
late-linear, narrow and entire, canescent with appressed, strigose hairs; flow- 
ers Solitary, sessile, or short pedunculate, scarcely arising beyond the sum- 
