146 BULLETIN 772, U. S. DEPARTMENT OF AGRICULTURE. 
Chaboissaea Fourn., Mex. Pl. 2: 112. 1886. A single species, C. ligulata, is 
included. This is Wuhlenbergia liguiata (Fourn.) Scribn. and Merr. 
Muhlenbergia is a somewhat artificial genus, including species of 
very diverse habit. It differs from Sporobolus in the 3-nerved awned 
or mucronate lemma, and from Agrostis in the firmer lemma, usually 
longer than the glumes. One group, including I/. squarrosa (Trin.) 
Rydb. (fig. 81), I. repens (Presl) Hitche., and their allies, has been 
usually referred to Sporobolus. The species of this group are in- 
cluded in Muhlenbergia because of the 3-nerved mucronate or awned 
lemmas, but they form a distinct section or possibly a distinet genus. 
Fig. 81.—WV uhlenbergia squarrosa. Plant, X 4; spikelet and floret, X 5. 
In &/. repens the lateral nerves of the lemma are commonly obsolete, 
and the apex is sometimes scarcely mucronate. : 
Of the species found in the United States two are annuals, d/. de- 
pauperata Scribn., with acuminate or awned glumes, and I. miecro- 
sperma (DC.) Kunth, with obtuse glumes, both growing in the ex- 
treme Southwest. The latter species produces cleistogenes in the axils 
of the lower sheaths. Muhlenbergia mexicana (L.) Trin. and its 
allies have branching stems and numerous panicles. The glumes are 
