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 

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

 i 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. 



9 

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



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



a 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. 



Camptjlosus. 



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-fid., 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 1-2-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. 



045 



