AND GENERA OF PLANTS. 341 



Psilocarphus * Oregonus; every where canescently tomentose, procumbent, 

 and diffusely branched; leaves linear, acute, with minute sphaceolous tips; fe- 

 male florets about twenty-five; masculine five; fructiferous scales uncinate. 



Hab. In inundated places near the Oregon and outlet of the Wahlamet. Nearly allied to 

 P. globiferus, but with much narrower leaves, and none of the long arachnoid hairs of that species 

 so conspicuous on the under side ; the scales of the receptacle are also smaller. 



Psilocarphus *teneUus; ascending, slender and much branched, below smooth; 

 leaves spathulate-linear, narrow; capituli mostly terminal, subtended by ap- 

 proximating, canescently tomentose, spathulate-oblong, acute leaves; feminine 

 florets about twenty-five; masculine about five; achenium minute, the scales 



with uncinate tips. 



Hab. Near St. Barbara, Upper California. Flowering in April. About two inches high, slen- 

 derly and diffusely branched. Very distinct from the preceding, having very narrow, smooth 

 leaves below, and almost an involucrum of broader canescent leaves above. Flowers minute. 



Tribe lY. —SENECIONIDEjE. 

 Division III. — SiLPHiEiE. 



SILPHIUM. (Linn.) 



Silphium ^radula; exceedingly scabrous; stem terete, leaves alternate, cor- 

 date-ovate, acuminate, semiamplexicaule, the lower ones subserrate; flowers 

 few, corymbose, rays about thirty; outer sepals ovate, the inner wide, ovate, 

 obtuse; wing of the smooth achenium very wide, the awns confluent. 



Hab. Plains of Arkansa. Allied to S. jlsteriscus. Three or four feet high, leaves three or 

 four inches long, by one and a half inches wide. Capitulum large, the larger sepals three-fourths 

 of an inch wide. 



Silphium * speciosum; stem terete, grooved, smooth and glaucous; capituli 

 corymbose ; leaves opposite, the uppermost alternate, cordate-ovate, acuminate, 

 amplexicaule, the lower subserrate, above, as well as the outer sepals, lanceo- 

 late, or ovate-lanceolate, the inner broad ovate, acute; rays about twenty-eight 

 to thirty ; wing of the smooth achenium very wide, the awns confluent. 



Hab. JVith the above, to which it is nearly allied, though distinct in the leaves being strictly 

 opposite, the stem glaucous, &c. A very showy species, as large, or larger than the preceding. 



Silphium * lanceohtum; stem terete, above hirsute, somewhat scabrous ; 

 leaves opposite, lanceolate, acuminate, shortly petiolate, repandly dentate, 



VII. — 4 L 



