410 cl vii. GRAMiNEiE (Stapf). [Heteroppgon. 
50. HETER0P0G0N, Pers. ; Benth. et Hook. f. Gen. PI. iii. 1133. 
Spikelets 2-nate, those of the lower (1 to many) pairs alike in sex 
and shape, rj or neuter, of the upper pairs differing in sex and 
strikingly so in. shape, one of each pair sessile,* the other pedicelled 
on the many- jointed rhachis of solitary racemes, terminating the 
culms and their upper branches ; rhachis tough or upwards tardily 
disarticulating -and glabrous between the homogamous pairs, readily 
disarticulating above them ; homogamous pairs long-persistent, 
the spikelets of the heterogamous pairs falling separately, the 
pedicelled with the pedicel, the sessile with the adjacent joint and 
the adjacent pedicel or its base. Florets 2, lower reduced to an 
empty valve, upper $ or in the sess il e spikelets of the hetero- 
gamous pairs, or neuter in all the other spikelets. Fertile spikelet 
terete or subterete, awned ; callus long, pungent, densely bearded 
upwards. Glumes equal ; the lower coriaceous, rarely chartaceous, 
more or less tightly involute, quite keelless, nerves obscure, often 
connected by few transverse nerves in the upper part ; the upper 
with a deep longitudinal groove on each side, coriaceous, rarely 
chartaceous, between them, thinner towards the margins, membranous 
at the tips, 3-nerved. Valve of lower floret hyaline, nerveless, of 
upper floret stipitiform from a hyaline very slender base, cartila- 
ginous upwards and passing into a usually stout geniculate awn. 
Valvule small or 0. Lodicules large or more or less reduced, to very 
minute. Stamens 3, often rudimentary, or 0. Stigmas exserted 
terminally or laterally. Grain more or less linear in outline, sub- 
terete, slightly dorsally compressed ; embryo somewhat exceeding 
the middle of the grain. Male (or neuter) spikelets dorsally flattened, 
usually slightly asymmetric, and often somewhat twisted, muticous, 
imbricate. Lower glume herbaceous, many-nerved, winged upwards 
from one or both keels ; upper membranous, lanceolate-oblong, 
acute, 3-nerved. Valves hyaline, 1 -nerved, well developed or more 
or less reduced. Stamens 3 or 0. — Perennial or annual grasses, 
with simple or more often upwards branched culms ; branches few 
to many, mostly flowering and gathered into a spatheate panicle ; 
racemes conspicuously dorsiventral, the bases of the $ (or neuter) 
spikelets subimbricate on the back of the raceme, their upper parts 
bending forward around the sides, forming a hollow in which the 
fertile spikelets are enclosed, with their awns exserted anticously 
and often intertwisted. 
Species about 4, in the tropical and subtropical regions of both hemispheres. 
Perennial ; leaf-sheaths conspicuously compressed and 
keeled ; lower blades usually shortly acute to subobtuse ; 
pedicelled spikelets oblong-lanceolate, subacute, 4-5 lin. 
long, their lower glume without a longitudinal median 
series of depressed glands ... ... ... ... ... L H. contortus 
Annual ; leaf-sheaths terete or only slightly compressed ; 
nil the blades long-tapering to a fine point ; pedicelled 
