ANALYTICAL KEY TO THE GENERA OF THE 

 FAMILY GRAMINE/E, 



INCLUDING GENERA CULTIVATED WITHIN THE 

 RANGE OF THIS WORK. 



PREPARED BY 



KARL M. WIEGAND. 



NOTE. The scales borne on the primary axis of the spikelet are termed 

 glumes; the one on each secondary axis is termed the palet. The two lowest 

 glumes, termed empty glumes, inclose no flowers and frequently differ from the 

 other glumes. Rarely there are more than two empty glumes, sometimes one, 

 or none at all. 



Make a careful dissection of the spikelet before using the key. Count the 

 nerves by transmitted light if possible. 



e.g. = spk. means, at least one empty glume equal in length to the spikelet 

 or longer, e.g. < spk. means, both empty glumes shorter than the spikelet. 



The names in parenthesis represent genera in cultivation only. 



a An ivory-like ovoid capsule at base of each fl. cluster, from an orifice in the 



top of which the stam. spikelets project (Coix.) 



aa No such ivory-like capsule. 



b Pist. spikes axillary, grown together forming a cob, the whole inclosed in a 

 leafy involucre; stam. inf. terminal; stout leafy grasses with broad leaves. 



(ZEA.) 



bb Inflorescence not as above. 



c Glumes or glume-like involucre bearing on the surface hooked or straight 

 spines or prickles. 



d With hooked prickles. . . . NAZIA. 



dd With straight or slightly curved spines. 

 e One recurved spine from middle of glume; spike dense, one-sided. 



CAMPULOSUS. 



ee Several spines on the globular involucre CENCHRUS. 



cc Glumes not spiny nor prickly. 



d Spikelets in distinctly one-sided spikes or spike-like panicles. 

 e Spikelets laterally compressed; glumes keeled. 

 f Some of the glumes long-pointed or awned, or 3-toothed. 

 g Spikelets 3- or more-fld., in panicles or spikes; glumes 5 or more; e.g.<spk. 

 h Spikelets regularly imbricated in 2 rows on one side of axis of solitary 



or digitate spikes DACTYLOCTENIUM. 



hh Spikelets fascicled at apex of stiff branches of the interrupted, spike- 

 like or open, one-sided panicle DACTYLIS. 



gg Spikelets i-2-fld., often with some rudimentary modified fls.; in true 



spikes only; normal glumes 3 or 4. 

 h Normal glumes 4; spikes somewhat whorled; fl. gl. much broader 



than e.g., usually with subapical awn; e.g. < spk CHLORIS. 



hh Normal glumes 3; sometimes also abnormal ones besides. 



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