386 MISC. PUBLICATION 243, U.S. DEPT. OF AGRICULTURE 
Racemes 3 to 8 em long, few, exserted. 
Guim blades 10 te 20’em longs 222) 2- 11. A. SALZMANNI. 
Culm. blades 2. te.5. em long.J.- =. nse 12. A. PARVIFOLIUS. 
Spikelets awned. 
First glume of sessile spikelet villous__________ 13. A. HIRTIFLORUS. 
First glume of sessile spikelet glabrous or nearly so. 
Blades terete, filiform; sessile spikelet 1.5 mm broad. 
16. A. MULTINERVOSUS. 
Blades flat or folded or sometimes involute toward the apex. 
Sessile spikelet about 4 mm long, 1 mm wide; blades not more 
than”l tb mmiswide! Vslehe si) Rl chs 4 es es 15. A. TENER. 
Sessile spikelet about 5 mm long; blades 2 to 5 mm wide. 
14. A. SEMIBERBIS. 
-Racemes more than one at the summit of the culms and branches (one of the 
pair occasionally abortive in A. urbantanus). 
Racemes several or numerous in an exserted panicle. 
Pedicellate spikelet about as large as the sessile. 
First glume of sessile spikelet pitted on the back____30. A. PERTUSUs. 
First glume of sessile spikelet not pitted ________- 31. A. ISCHAEMUM. 
__ Pedicellate spikelet much smaller than the sessile___29. A. SACCHAROIDES. 
Racemes 2 to 4 (sometimes more in A. selloanus), fascicled, subtended by a 
bladeless sheath (spathe), exserted or partly included. 
Spikelets awnless. 
Plants robust, 1.25 to 2 m tall; spathes aggregate in a corymbose, usually 
deniseinflorescenGes) 202 Psst. We DS Ba a ee 18. A. BICORNIS. 
Plants slender, usually less than 1 m tall; spathes not aggregate. 
Sessile spikelets about 3 mm long; blades usually not more than 2mm 
wide, the apex acuminate_____________ 19. A. LEUCOSTACHYUS. 
Sessile spikelets about 4 mm long; blades 3 to 5 mm wide, the apex 
boat-shapede). 0) 2) GEE ee eee 8 eee 20. A. SELLOANUJS. 
Spikelets awned. 
Pedicellate spikelet as large as the sessile______-__~_- 21. A. LATERALIS. 
Pedicellate spikelet reduced. 
Racemes densely white-woolly, the hairs almost hiding the spike- 
letS 5.882224 2ceud eu: 2 = Ee ee 22. A. NASHIANUS. 
Racemes more or less villous, but the hairs not hiding the spikelets. 
Blades involtite, ‘firmy! 20) 01!14 9) Cs Bie er 23. A. URBANIANUS. 
Blades flat or folded, comparatively soft. 
Sheaths, especially the upper, long and inflated, more or less 
aggregate, the spathes inconspicuous__-_-_-_ 24. <A. ELLIOTTII. 
Sheaths not conspicuously inflated. 
Spathes aggregate in a compound flabellate or club-shaped 
inflorescences 293) 2 2 51S ee See 25. A. GLOMERATUS. 
Spathes sometimes numerous but not aggregate in a compound 
club-shaped inflorescence. 
Peduncle of the 2 racemes 3 to 5 em long. 
Pedicellate spikelet wanting or nearly so. 
27. <A. REINOLDII. 
Pedicellate spikelet prominent but the awn reduced. 
28. A. ANGUSTATUS. 
Peduncle of racemes less than 1 em long. 
26. A. VIRGINICUS. 
1. Andropogon condylotrichus Hochst.; Steud., Syn. Pl. Glum. 1:3 77. 
1854. Abyssinia. 
Andropogon piptatherus Hack., in Mart., Fl. Bras. 2°: 293. 1883. 
Brazil. 7 
Sorghum piptatherum Kuntze, Rev. Gen. Pl. 2: 792. 1891. 
Amphilophis piptatherus Nash, N. Amer. Fl. 17: 127. 1912. 
Euclasta condylotricha Stapf, in Prain, Fl. Trop. Afr. 9: 181. 1917. 
Weak-stemmed branching annual; culms 1 to 2 m long, the nodes 
villous; blades 15 to 20 cm long, 4 to 8 mm wide, setaceous-pointed ; 
racemes several, fascicled, 2 to 5 cm long, on slender flexuous 
peduncles; pediceled spikelets about 5 mm long; spikelets, rachis 
joints, and pedicels loosely pilose. 
