198 A TEXT-BOOK OF GRASSES 
FF. Inflorescence an open or contracted 
but not densely cylindrical pan- 
icle; glumes not compressed- 
carinate and ciliate. 
Gc. Glumes saccate at base; lemma 
long-awned; inflorescence con- 
tracted, shining; annuals..... GASTRIDIUM. 
aa. Glumes not saccate at base. 
H. Lemma bearing an awn several 
times its length; annuals 
with open panicles.......... APERA. 
HH. Lemma short-awned, or awn- 
less, the palea often reduced 
Ge weir. (gece. cece AGROSTIS 
pp. Glumes as long as, or shorter than the (Par. 234). 
lemma. 
E. Lemma bearing a tuft of hairs at 
base from the short callus. 
F. Lemma and palea thin............ CALAMAGROSTIS 
FF. Lemma and palea chartaceous. (Par. 235). 
G. Panicles spike-like; rachilla pro- 
IGM eee Oe ee ee AMMOPHILA 
ac. Panicles open; rachilla not pro- (Par. 236). 
RS Se tootsie ce ho CALAMOVILFA. 
EE. Lemma without hairs at base. 
F. Palea apparently 1-nerved, the 2 
nerves close together; rachilla 
prolonged; panicle open......... CINNA. 
FF. Palea distinctly 2-nerved; rachilla 
not prolonged. 
c. Nerves of lemma densely silky.. BLEPHARO- 
aa. Nerves of lemma not silky. [NEURON. 
H Fruit not inclosed in the 
lemma and palea, seed usually 
also loose in the pericarp, 
this opening at maturity... .SPOROBOLUS. 
HH. Fruit inclosed in the lemma 
and palea; the seed also 
inclosed in the pericarp at 
maturity and grown to it; 
panicles spike-like in our 
species. 
1. Panicles short, partly in- 
closed in the upper sheath; 
sparingly introduced from 
ine Old. Wortd.... 52.5.5 HELEOCHLOA, 
m1. Panicles elongated; tall per- 
ennials of Arizona and 
southward.......... +:+++lPICAMPES. 
