AND GENERA OF PLANTS. 415 
lanceolate. Stamens and stigmas not exserted, very short.—This plant appears to have no relation 
to Senecio. ‘The general appearance of the flower is moe like that of Chrysanthemum segetum. 
$: eh 
TE TRADYMIA. - alee wb 
ar 
-Capitulum homogamous, four-flowered. The involucrum of four biserial, foli- 
aceous, oblong, obtusely carinated sepals, the inner membranaceous on the 
margins. Rece ) ta le naked and narrow. Corolla tubular, deeply five-cleft, 
the lobes linear. Branches of the stigma nearly terete, the apex obtuse and 
hirsute. Achenium turbinate, densely villous with simple hairs. Pappus — 
copious, in many series, the sete all equal, rather rigid and barbellate— 
Canescent, much branching, and sometimes spiny shrubs of the plains of 
the Rocky Mountains or Northern Andes. Leay ponte sessile, fasci- 
culate in the axills, entire and linear. Capituli in rminal fascicles or ra-_ 
cemes, “Same Flowers deep yellow. 
Teisallynise ditions. (Decanp.;) leaves mucronate; capituli racemose. 
Has. Oregon; (Douglas.) Ihave never seen this species, and think it more probable to be a 
native of California, or the Rocky Mountains. Certainly not along the plains of the north-west 
coast. 
Tetradymia * inermis; shrubby, much branched, and canescently tomentose; 
leaves oblong-linear, slightly acute, somewhat clustered; capituli in terminal 
clusters of three to five, upon short peduncles, the central ones often sessile. 
Has. On the dry barren plains of the Rocky Mountains; common, particularly near Lewis’ 
River, of the Shoshonee, but not in the plains of Oregon. A much branched shrub, two or three 
feet high, whitely canescent with a close soft tomentum, which is also spread over the branches; 
the branches studded with the cicatrices of former buds. Leaves about three-quarters of an inch 
long, often obtuse, slightly apiculated. Sepals oblong, obtusely_ carinated, connected at base. 
-Achenium thickly clad with long simple hairs, beneath which it is entirely hid; the pappus very 
copious and long, at length longer than the florets, becoming pale brown, the sete Eaner. slender, 
and all similar; at pee growing out to the length of half an inch. ae 
Tetradymia le eanescently tomentose, shrubby and ich trancit 
axills spinescent; leaves Hinear-oblong, obtuse or acute, clustered, at 
nearly smooth; capituli in terminal clusters, pedunculate. 
Has. With the above, on the dry plains of Lewis’ River, and on Ham’s Fork of the Colac of 
the West: common. Flowering in July. A very elegant and singular. ‘shrub, growing in tufts, 
