CATALOGUE. 125 



Petalonyx Thurberi, Gray (Bot. Mexican Boundary, tab. 22). — South- 

 ern Nevada. 



Petalonyx nitidus, Watson (Amer. Naturalist, 7, 300). — Differing 

 from the above in having its leaves distinctly petioled, serrate, " vitreous 

 and shiny" and nearly alike in size (1-1 1' long) to the ends of the 

 branches. Flowers also are in short, dense, cymose panicles. — Also 

 from Southern Nevada. — Plate IV. Fig. 1. Branch nearly natural size. 

 2. Flower. 3. A single petal. 4. Diagonal section through pistil show- 

 ing the single suspended ovule and two calyx-lobes. All except the branch 

 enlarged. 



Mentzelia nuda, T. & G. — 6-18' high, very rough, with short, 

 almost cartilaginous bristles, usually branched from the root; leaves 

 linear or lanceolate, nearly entire, or deeply pinnatifid ; exterior filaments 

 more or less dilated, antheriferous ; petals nearly or about twice as 

 long as the linear calyx-segments ; seeds very numerous, winged, and 

 somewhat flat. — Colorado (764, 765); Fort Wingate, N. Mex., Professor 

 Loew, coll. 



Mentzelia aspeea, L. — Annual ; usually slender leaves, 3-lobed (the 

 terminal lobe largest, irregularly toothed) ; petioles 4" long, slender ; flowers 

 sessile or nearly so ; petals 2" long, equalling the subulate calyx-teeth ; 

 capsule V long, regularly club-shaped. The few flattish seeds pendulous, 

 under the lens marked with curved longitudinal lines. Not winged. — 

 Sanoita Valley, Arizona, at 6,000 feet altitude (642). I had doubtfully 

 named this M. albicaulis, Dougl., but from Mr. Watson's description in Fl. 

 Cal. 1, p. 235, have assigned it here. Number 1)28 of Thurber's collection 

 is in part the same, but is under M. albicaulis. 



Mentzelia albicaulis, Dougl. — Colorado (768) ; Nevada. 



Mentzelia l^evicaulis, T. & G. — Utah. 



linear-oblong, pilose, 2-lobed at base, connective produced beyond the anther-cells into an elongated 

 sub-inflated process. Staminodia 0. Ovary inferior, 1-celled; style short, stigma ovoid. Solitary 

 ovule hanging from the apex of the cell. Fruit dry, indehiscent, oblong or obovoid, crowned by 

 the calyx and corolla. Exalbuniinous seed, conformed in shape to the cell ; testa membranaceous, 

 smooth; cotyledons amygdalino; radicle very short. — Branching herbs, with the habit of Scabiosa, can- 

 escent-pubescent, setose, with larger simple bristles arising out of glands, smaller ones short, thick 

 [transversely tubercular roughened] ; bark white, shining. Sessile leaves alternate, sinuate-pinnatifid. 

 Flowers terminating the peduncles, aggregated in hemispherical heads, silky hirsute. Involuore of 

 linear-setaceous bracts. — Bentham & Hooker. 



