22 



POACEAE. 



9. CHAETOCHLOA Scribn. (Setaria Beauv. 1812. Not Ach. 1798.) 

 Mostly annual grasses with erect culms and flat leaves, the inflorescence 

 in spike-like clusters. Spikelets 1 -flowered, or rarely with a second staminate 

 flower, the basal bristles single or in clusters below the articulation of the 

 rachilla, and therefore persistent. Scales of the spikelet 4, the three outer 

 membranous, the third often subtending a palet and rarely a staminate flower ; 

 the inner or fourth scale chartaceous, subtending a palet of similar texture and 

 a perfect flower. Stamens. 3. Styles distinct, elongated. Stigmas plumose. 

 Grain free, enclosed in the scales. [Greek, in reference to the bristles of the 

 inflorescence.] Species about 35 in temperate and tropical regions. Type 

 species : Setaria longiseta Beauv. 



Annuals. 



Bristles downwardly barbed. 



Bristles upwardly barbed. 

 Perennial ; bristles upwardly barbed. 



1. C. verticillata. 



2. C. viridis. 



3. C geniculata. 



1. Chaetochloa verticillata (L.) 

 Scribn. Fox-tail Grass. (Fig. 28.) 

 Culms erect or decumbent, l°-3° tall. 

 Sheaths glabrous; leaves 2'-8' long, sca- 

 brous above; spikes 2'-3' long, green or 

 purple, 6"-8" thick; spikelets about 1" 

 long, equalled or exceeded by the down- 

 wardly barbed bristles; bristles 1-3 

 at the base of each spikelet, not involu- 

 crate; first scale less than one half as 

 long as the spikelet, 1-nerved; second 

 and third scales 5-7-nerved, equalling 

 the oval fourth one. [Setaria verticil- 

 lata Beauv.] 



Common as a weed in waste and cul- 

 tivated grounds. Naturalized. Native of 

 the Old World. Naturalized in the southern 

 United States and in tropical America. 

 Flowers nearly throughout the year. 



2. Chaetochloa viridis (L.) Scribn. 

 Green Fox-tail Grass. (Fig. 29.) An- 

 nual, culms l°-3° tall. Sheaths glabrous; 

 leaves 3-10' long, 2' -6" wide; spikes 1- 

 4' long; spikelets about 1' long, elliptic, 

 much shorter than the green, or some- 

 times yellowish, bristles; first scale less 

 than one half as long as the spikelet, 1-3- 

 nerved; second and third scales 5-nerved; 

 fourth scale equalling or slightly exceed- 

 ing the second. [Setaria viridis Beauv. [ 



Common as a weed in waste and cul- 

 tivated grounds. Naturalized. Native of 

 Europe. Widely naturalized in North 

 America. Flowers from spring until autumn. 



Chaetochloa magna (Griseb.) 

 Scribn., a very large West Indian species, 

 was, apparently, collected in Bermuda 

 by Munro in 1864, but is not known to 

 grow here now. 



