54 GRAMINACEAE 



Zea — Corn, Maize 



(Gr. zeia, a kind of coarse grain) 

 A single cultivated species Z. mays 



Coix — Job's Tears 



(Gr. koix, a kind of palm) 

 A single cultivated species ('. Idchryma 



ANDR0P0GONEAE BLUESTEM TRIBE 



1. Spikelets in many-jointed, spike-like hairy racemes Andropogon 



2. Spikelets in a panicle 



a. Panicle very hairy, golden, stalked spikelets reduced to 1 or 2 hairy 



pedicels Chrysopogon 



b. Panicle smooth or nearly so, brownish, stalked spikelets 1-2, staminate 



° r empty Sorghum 



Andropogon — Bluestem, Beard Grass 



(Gr. aner, andros, man, pogon, beard, referring to the hairy axis) 



1. Racemes solitary, stems 4-8 dm. high A. scopdrius 



2. Racemes in clusters, stems 10-15 dm. high A. furcdtus 



Chrysopogon — Goldstein, Goldbeard 



(Gr. chrysos, gold, pogon, beard, referring to the hairy pedicels) 

 A single species C . nutans 



Sorghum — Sorghum 



(Of doubtful origin and meaning) 

 A single cultivated species $. vulgaris 



PAN ICE AE— MILLET TRIBE 



1. Spikelets inclosed in a spiny bur Cenchrus 



2. Spikelets not inclosed in a spiny bur 



a. Spikelets borne in more or less one-sided spikes 



(1) Spikes long and slender, in a digitate cluster; glumes not awned Digitaria 



(2) Spikes shorter, in a panicle; glumes more or less awned Echinochloa 



b. Spikelets not in one-sided spikes 



(1) Spikelets subtended by bristles, in a cylindrical spike Setaria 



(2) Spikelets not subtended by bristles, in a panicle Panicum 



Cenchrus — Sandbur 



(Gr. name of a kind of millet) 

 A single species c carolinidnus 



Digitaria — Finger Grass 



(Lat. digitus, finger, referring to the flower cluster) 



1. Axis of spikes flat, broadly winged; stems spreading 



a. Spikelets with 3 glumes, 2-3 mm. long D . sanguindlis 



b. Spikelets with 2 glumes, 2 mm. long £>, humijusa 



2. Axis of spikes not winged, 3-angled, stems erect D. filiformis 



Echinochloa— Barnyard Grass 



(Gr. echinos, hedgehog, chloe, grass, referring to the bristly spikelets) 

 A single species with awned spikelets, awn very variable in length E. crusgdlli 



Setaria — Foxtail, Pigeon Grass 



(Lat. seta, bristle, referring to the awns) 



1. Bristles five or more below each spikelet S. glduca 



2. Bristles 1-3 below each spikelet 



a. Spikes thick and dense, 1-2 dm. long, spikelets 3 mm. long S. itdlica 



b. Spike slender, 3-10 cm. long, spikelets 2 mm. long S. viridis 



