296 BOTANY. 



4-6" long.— Gila Valley, Arizona, 1874 (334). Var. pauciflora much 

 smaller and more delicate ; leaves broader and shorter and not scabrous ; 

 panicle much smaller and looser, is 2096, C. Wright, N. Mex. Coll., 1851 and 



1852. 



Helopus punctatus, Nees. — This differs from Panicum in having 

 clavate, torulose pedicels, and in the absence of the inferior glume. Culm 

 erect, 2-3° from a decumbent base, somewhat pubescent at the nodes, 

 ligule a short pubescent fringe; leaves lanceolate-linear, 6-10' long, 3-5" 

 wide, smooth; panicle 6' long, of 5-10 erect, sessile branches; axis and 

 rays pubescent; pedicels clavate, with a short ring-like torus; spikelets 

 l£-2" long, acuminate, finely pubescent ; glume and sterile flower pointed ; 

 perfect flower oval or oblong, mucronulate, punctate. — Cienega, Arizona, 

 1 874 (583). 



Andeopogon macrourus, Michx. — Southern Nevada and Arizona, 

 1871 and 1872. 



Andropogon argenteus, Ell. — Arizona, 1871 and 1872. Sulphur 

 Springs, Arizona, 1874 (547). 



Andropogon scoparius, Michx. — Black River Flats, Arizona, 1 874 (790). 



Andropogon ciliaris, Trin (Elionuriis ciliaris, H. B. K. ) — This belongs 

 to a section of Andropogon which is distinguished by having the spikes 

 solitary, lateral, and terminal. Root fibrous, red, aromatic ; culms csespitose, 

 ascending or erect (3-4°), compressed ; ligules short, ciliate ; leaves nar- 

 rowly linear or filiform-involute, glabrous, or pilose below ; spikes 2—4' 

 long, jointed ; male spikelet with a short, ciliate, margined pedicel ; perfect 

 spikelet sessile, the lower glume acutely bifid at the apex, white hairy 

 externally. — Sanoita Valley, Arizona, 1874 (638). 



Andropogon contortus, L. (Heteropogon hirsutus, Pers.) — This belongs 

 to the same section as the preceding. Culm erect, branching, 1—2°, 2- 

 edged below ; sheaths and nodes glabrous ; ligule short, truncate, ciliate ; 

 leaves flat, sharp-pointed, scabrous ; spikes solitary ; rachis and pedicel of 

 the fertile flowers hirsute ; outer glume of male flower acute and pilose ; 

 awn long (3').- — Sanoita Valley, Arizona, 1874 (656). 



Sorghum nutans, Gr. — Sanoita Valley, Arizona, 1874 (689). 



Imperata arundinacea, Cyrill. — Spikelets in pairs, one sessile, the other 



