168 MR. NUTTALL'S DESCRIPTIONS OF NEW 



§. *Ptilosepala. Perianth exserted ; the segments oblong, deeply fringed towards 

 their base, (red,) styles very long. 



C. *FiMBRiATA. Annual ; leaves all radical, spathulate-oval, pilose beneath ; scape trichotomous ; flowers 

 in compound cymes ; involucrum pubescent, the teeth subulate, unequal ; perianth torn at the sides 

 into long capillary fringe. 



Three to five inches high, erect, with a rather large trichotomous cymose panicle, 

 the flowers sessile and mostly distinct. Segments of the perianth exserted, bright 

 rose red below, within the involucrum membranous. The joints of the cyme fragile. 



Hab. With the above. (Nuttall.) 



PTEROSTEGIA. 



P. *DiPHYLLA. ©. Pubescent; leaflets binate, each division obcordate or bilobed ; common petiole on the 

 lower leaves very long ; achenium with the angles acute. 



yS. *BiLOBA. Leaves nearly all two-lobed, the lobes sometimes emarginated. 



A diffuse prostrate annual, with straggling forked branches, the leaflets almost 

 like some Oxalis, small, about three to four lines long, and about the same breadth, 

 the lower petioles more than an inch long ; margins of the two-leaved involucrum 

 denticulate, scattered, with small hooked hairs, the crests nearly entire on the 

 margin, and partly folded up at the lower edge. 



Hab. Near Santa Barbara. Flowering in May. 



P. *MicR0PHYLLA. Q. Somewhat hirsute; leaflets binate, the lower ones twice compounded, divisions 

 obcordate or unequally bilobed, the lobes sometimes with a single tooth ; common petiole on the lower 

 leaves elongated, the upper leaves sessile ; achenium with obtuse angles. 



Hab. With the above, which it greatly resembles, but always smaller leaved and 

 more pubescent. 



*NEMACAULIS.t 



Involucrum, none ; the flowers monoicous, disposed in round clusters at the joints 

 of the filiform stem, subtended and mixed with elliptical bractes. Perianth obconic, 

 six-cleft. Stamens three. Styles three, very short, with small subcapitate stigmas. 

 Achenium ovoid, angular only at the summit. — Californian annuals, the leaves 

 wholly, and the bractes on the upper side densely and whitely tomentose ; stems 

 smooth or viscid, filiformly elongated and nearly naked, with the flowers disposed in 

 sessile round heads at the joints of the stem, and subtended and mixed with small, 

 elliptical, marginated bractes. The flowers resemble those of Eriogonum, but the 

 habit, absence of involucrum, and paucity of stamens, at once distinguish it. 



N. *DENUDATA. Roots loHg and slender, filiform. Leaves spathulate-cuneate, attenuated below into a 

 petiole one and a half to two inches long, densely lanuginous, stems three to five from the same root, 



t From the singular prostrate, thread-like stem. 



