20 BULLETIN 772, U. S. DEPARTMENT OF AGRICULTURE. 
Key to the genera of Paniceae — Continued. 
12a. Spikelets in slender racemes more or less digitate at the 
summit of the culms 110. Syntheeisma. 
12b. Spikelets in panicles 13 
13a. Fruiting lemma boat shaped; panicles narrow. 
108. Anthaenantia. 
13b. Fruiting lemmas convex; panicles diffuse— 111. Leptoloma. 
10b. Fruit chartaceous-indurate, rigid 14 
14a. Spikelets placed with the back of the fruit turned away from 
the rachis of the racemes, usually single (not in pairs) 15 
15a. First glume and the rachilla joint forming a swollen ring- 
like callus below the spikelet 113. Eriochloa. 
15b. First glume present or wanting, not forming a ringlike 
callus below the spikelet 16 
16a. First glume present ; racemes racemose along the main 
axis 114. Beachiaeia. 
16b. First glume wanting ; racemes digitate or subdigitate. 
115. Axonopus. 
14b. Spikelets placed with the back of the fruit turned toward the 
rachis of the spikelike racemes, or pedicellate in panicles 17 
17a. Fruit long-acuminate; both glumes wanting- 116. Reiataeochloa. 
17b. Fruit not long-acuminate, at least one glume present 18 
18a. First glume typically wanting; spikelets plano-convex, 
subsessile in spikelike racemes 117. Paspalum. 
18b. First glume present ; spikelets usually in panicles 19 
19a. Second glume inflated-saccate, this and the sterile 
lemma much exceeding the stipitate fruit. 
120. Sacciolepis. 
19b. Second glume not inflated-saccate 20 
20a. Culms woody and bamboolike; fruit with a 
tuft of down at the apex 119. Lasiacis. 
20b. Culms herbaceous ; no tuft of down at the apex 
of the fruit 118. Panicum. 
Tbibe 13, Andbopogoneae. 
Spikelets in pairs along a rachis, the usual arrangement being 
one of the pair sessile and fertile, the other pedicellate and staminate 
or neuter, or rarely wanting, only the pedicel present ; fertile spike- 
let consisting of one perfect terminal floret and, below this, a stami- 
nate or neuter floret, the lemmas thin or hyaline, and two awnless 
glumes, one or usually both firm or indurate. 
A large tribe, confined mostly to warm regions. The rachis is 
usually jointed, disarticulating at maturity, with the spikelets at- 
tached. In a few genera it is thickened. Sometimes the racemes are 
shortened to 1 or 2 joints and borne on branches, the whole forming a 
panicle (as in Holcus and Sorghastrum) instead of a series of 
racemes. In a few genera the spikelets of the pair are alike. In 
Trachypogon the fertile spikelet is pedicellate and the sterile one 
nearly sessile. 
