_. AND GENERA OF PLANTS. 417 
Lagothamnus * ambiguus; with the whole aspect and character of the pre- 
ceding, but with the divisions of the involucrum all obtuse; the false pappus of 
the sides of the achenium more copious, and the inner true pappus so slender 
as to be scarcely distinguishable. 
Has. With the above. 
. Appendix to Senectonipez. Subtribe MELAMPODINE. 
Division u. Mim.erirx? 
* PICROTHAMNUS. 
Capitulum monoicous, heterogamous, few-flowered; rays feminine, (three to 
five,) tubular, truncated, two or three-toothed; discal florets masculine, with 
abortive styles, (five to ten,) globose-ovate, five-toothed, teeth triangular, and, 
as well as the rays and achenium, copiously clothed with long flaccid hairs, 
the tube very slender. Receptacle naked, very small. Involucrum hemi- 
spherical, imbricate, about five-leaved, the leaves rounded. Style bifid, 
stigmas terete-cylindric, with a minutely pencillated summit, nearly smooth. 
Achenium obconic, turbinate, subcylindric, without pappus, sending off, up- 
wards, numerous long, tortuous hairs. Discal florets without any rudiments 
of fruit.—A low, much-branched, inelegant, spiny shrub, somewhat softly 
lanuginous. Leaves alternate, twice trifid. With the habit of an Artemisia; 
capituli’in short, leafy racemes, the rachis of which, at length, becomes a 
long spine. Florets pale yellow.—(The name from mpos, bitter, and Gayo, 
_ a bush; in allusion to its bitterness. ) . 
Picrothamnus * desertorum. - 
Has. Rocky Mountain plains, in arid deserts, towards the north sources of the Platte. Root 
woody, much branched and very long, covered with numerous fibrous vestiges of bark. Stem 
from four inches to a foot or more, woody and branehed from the base; the whole plant hirsute 
and grayish canescent. Leaves twice trifid, pseudopetiolate, the segments short, oblong, and Tt 
A plant of very doubtful affinity, allied in some respects to Clibadium, and therefore to the division 
Mittert®. It is also allied to the Ivem; but the tube of anthers are uni 
vil.—5 E 
