340 DESCRIPTIONS OF NE^iV SPECIES 



*PSILOCARPHUS. 



Capituli many-flowered, heterogamous ; flowers all tubular; rays in several se-*- 

 ries, filiform, feminine; discal florets hermaphrodite, sterile, about five. In- 

 volucrum none, or mere foliaceous, irregular bractes. Receptacle convex^ 

 elevated, bracteolate, except the centre, bractes gibbous, subcylindric, reti- 

 culately membranaceous, folded inwards over the female florets and achenia. 

 Achenium cylindric-oblong, smooth and shining, loosely infolded and decidu- 

 ous with the bracteoles. — Dwarf annuals of North-Western America, with 

 the whole aspect of Micropus, diffusely branched, and canescently tomen- 

 tose; flowers glomerate, lateral and terminal. — (The name from ^t/los, slen- 

 der, and xap^os, chaff. In allusion to the membranous bracteal scales.) 



Psihcarphus * glohiferus; canescently tomentose, beneath more densely; 

 prostrate and diffusely branched, leaves oblong-linear, the floral ones broader, 

 obtuse; capituli lateral and terminal; female florets twenty-five to twenty-eight; 

 masculine five to eight; scales of the receptacle gibbous, rostrate, involute. — 

 Micropus glohiferus? Decand. and Bertero, Vol. V., p. 460. 



Hab. Round St. Barbara, Upper California. Flowering in April. Not an inch high, spread- 

 ing out five or six inches, beneath covered with a long, soft, white wool, above less densely canes- 

 cent, centre of the receptacle naked, convex and elevated ; masculine florets very minute. Fruc- 

 tiferous scales reticulately membranaceous, not in the least rigid, subcylindric, gibbous, with a 

 short rostrum. 



Psiloca7'phus *hrevissimus; canescently and very softly tomentose; stem 

 minute and very dwarf, producing mostly a single capitulum; leaves oblong- 

 lanceolate, acute; female florets about eight; fructiferous scale ovate-oblong, 

 without beak; achenium almost linear. — Micropus minimus? Decand., Vol. V., 

 p. 461. 



Hab. Plains of the Oregon River, in inundated tracts. Extremely dwarf, (perhaps not always 

 so.) About four lines high, the solitary capitulum, though rather large, sessile on about the third 

 set of leaves, and so downy as to look like a pellet of cotton, the fruit-bearing scale nearly quite 

 straight, scarcely gibbous, larger than usual; the achenium narrow, but longer than in the pre- 

 ceding, to which it, in fact, is closely allied. It does not appear to branch at all, and therefore is 

 scarcely the Micropus minimus; which, however, as well as the M. globiferus, no doubt belongs 

 to the present genus. 



