30 



Specimens examined.— 7>ro&- Laredo, Havard 1884; no locality, Nealley 1887,1888. 



Mexico: Mirado, .362 Liebmann 1841, cited by Fourn. Mex. PI. Enum. Gram. 45; 



Guaymas,53 E. Palmer 1887; no locality, 378,505, and 872 E. Palmer. 

 A distinct species, readily distinguished from C. composita (H. B. K.) Scribn. by its 



gibbous spikelets and broader, lanceolate leaves; and from other related species 

 ♦ by its dense subcylindrical panicles. 



20. CH-ffiTOCHLOA RIGIDA sp. nov. 



An erect, rigid perennial, 3 to 6 dm. high, with loose, narrow, interrupted panicles, 

 few short setse, and rigid, lanceolate leaves 1 to 2.5 dm. long. Culms cylindri- 

 cal, somewhat branching below, striate, smooth, scabro-pubescent below the 

 panicles and sometimes below the glabrous nodes; sheaths mostly close, equaling 

 or exceeding the nodes, glabrous, the lower ones imbricate and scarcely striate, 

 margins very smooth, not ciliate; ligule very short, sparingly ciliate, not exceed- 

 ing 1 mm. in length; leaf -blades rigid, 6 to 12 mm. wide, minutely scabrous on 

 both sides or nearly smooth, often minutely pubescent at the throat, serrulate- 

 scabrous on the margins, narrowed at the base, acuminate, sometimes somewhat 

 involute-setaceous above, midnerve very prominent on the lower side of the 

 leaf for two-thirds its length, glabrous. Panicle 0.5 to 2 dm. long, strict, often 

 scarcely exserted from the upper sheath, pale or straw-colored; rachis angular, 

 short pubescent or somewhat villous, undulate; branches very short or nearly 

 obsolete, the lower not exceeding 1 cm., erect; setae solitary, often nearly obso- 

 lete, stout, flexuous, 3 to 10 mm. long. Spikelets 2 to 2.5 mm. long, ovate, acute; 

 first glume about one-half as long as the spikelet, acute, 3-nerved, the midnerve 

 excurrent, the lateral ones anastomosing with it; second glume one-half to two- 

 thirds as long as the spikelet, 5 to 7 nerved, broadly ovate, acute, apiculate; 

 third glume equaling the flowering glume and slightly inclosing it with its 

 infolded margins, 5-nerved, sulcate, subtending a lanceolate, hyaline palea two- 

 thirds its own length; flowering glume ovate, acute, apiculate, obscurely keeled, 

 striate, transversely undulate-rugose below, nearly smooth and glossy at the 

 apex, the inclosed palea similar in markings and texture, nearly plane. 



Lower California. September-February. 



Specimens examined. — Lower California: La Paz, 125 E. Palmer 1890 (type) ; Carmen 

 Island, 857 Palmer 1890; San Jose del Cabo, 28 Brandegee 1890. 



All these plants were distributed under the names of Selaria eaudata and S. setosa, 

 from both of which this species is very distinct. Readily distinguished by its 

 rigid culms, smooth sheaths, narrow, straw-colored panicles, and few, usually 

 very short, setae. Related to C. macrostachya. 



densely bearded with stiff hairs; leaves 2 to 3 dm. long, 1.5 to 2 cm. wide; nodes 

 smooth. Panicle about 2 cm. in diameter; rachis scabrous, sparingly villous; 

 setse solitary, erect-siireading, 1 to 1.5 cm. long. Spikelets 3 mm. long, narrowly 

 ovate, acute; first glume one-third to one-half as long as the spikelet, acute, 3 to 

 5-nerved; second glume four-fifths as long as tlie spikelet, acute, apiculate, 7- 

 nerved, nerves prominent; third glume equaling the spikelet, 5-nerved, subtend- 

 ing a broad-lanceolate, hyaline palea its own length; flowering glume acute, 

 apiculate, strongly ti'ansversely undulate-rugose below, nearly smooth at the 

 apex, the inclosed palea striate. In the specimen examined the flowering glume 

 has a prominent hippocrepiform scar at the base. 



Australia. 



A species previously referred to C. macrostachya (H. B. K.), but from which it is at 

 once distinguished by its thicker panicles, broader leaves, narrowly ovate, larger 

 spikelets, and more strongly rugose flowering glume. 



