164 



GRAMINEAE. 



Vol. I. 



a palet and a perfect flower; the scales of the subterranean spikelets become indurated and 



enclose the grain. Stamens 3. Stigmas plumose. [Greek, from the two kinds of spikelets.] 



Species 2, one of them restricted to Florida. Type species : Milium Amphicarpon Pursh. 



i. Amphicarpon Amphicarpon (Pursh) Nash. 

 Pursh's Amphicarpon. Fig. 389. 



M. Amphicarpon Pursh, Fl. Am. Sept. 1 : 62. pi. 2. 1814. 

 Milium ciliatum Muhl. Gram. 77. 1817. 

 Amphicarpum Purshii Kunth, Rev. Gram. 28. 1829. 

 A. Amphicarpon Nash, Mem. Torr. Club, 5 : 352. 1894. 



Culms erect, i2'-i8' tall, slender, glabrous. Sheaths 

 papillose-hirsute; ligule pilose; blades i'-6' long, 2"-6" 

 wide, erect, acuminate, hirsute and ciliate; panicle 

 linear, 4'-6' long, branches 3-4, erect, bearing few 

 spikelets ; spikelets about 2" long, elliptic ; outer scales 

 S-nerved, membranous, glabrous ; subterranean spikelets 

 ovoid in fruit, about 3" long, acute, the scales all be- 

 coming much indurated. 



In moist pine barrens, New Jersey ; also in Florida (ac- 

 cording to Chapman). Aug.-Sept. 



21. CHAETOCHLOA Scribn. Bull. U. S. 

 Dep. Agr. Agrost. 4: 38. 1897. 

 [Setaria Beauv. Agrost. 113. 1812. Not Ach. 1798.] 

 Mostly annual grasses with erect culms, flat leaf-blades, the inflorescence in spike-like 

 panicles. Spikelets i-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, often becoming indurated in fruit, 

 subtending a palet of similar texture and a perfect flower. Stamens 3. Styles distinct, elon- 

 gated. Stigmas plumose. Grain free, enclosed in the scales. [Greek, bristly-grass.] 



Species about 35, in temperate and tropical regions. Type species : Setaria longiseta Beauv. 



Bristles downwardly barbed. 1. C. verticillata. 



Bristles upwardly barbed. 



Inflorescence racemose; second scale shorter than the spikelet; bristles 5-16, involucrate. 

 Annual; spikelets exceeding iJ4" long; bristles yellowish brown. 2. C. glauca. 



Perennial; spikelets ij4" long or less; bristles green, yellowish, or purple. 3. C. imberbis. 

 Inflorescence paniculate ; second scale as long as the spikelet ; bristles 1-3, not involucrate. 

 Fruiting scales dull, faintly rugose, obtuse, rather thin. 



Inflorescence i'-3 z /i' long, %' thick or less; spikelets about 1" long; bristles green. 



4. C. viridis. 

 Inflorescence 4'-9' long, $£'—2' thick; spikelets about 1%" long; bristles usually purple. 



5. C. italica. 

 Fruiting scales shining, perfectly smooth, very acute, hard. 6. C. magna. 



i. Chaetochloa verticillata (L.) Scribn. Fox- 

 tail-grass. Fig. 390. 



Panicum verticillatum L. Sp. PI. Ed. 2, 82. 1762. 

 Setaria verticillata Beauv. Agrost. 51.- 1812. 

 Chamaeraphis verticillata Porter, Bull. Torr. Club, 20: 196. 



1893. 

 Ixophorus verticillatus Nash, Bull. Torr. Club, 22 : 422. 



1895. 

 C. verticillata Scribn. Bull. U. S. Dep. Agr. Agrost. 4: 39. 



1897. 



Gulms erect or decumbent, i°-2° tall, more or less 

 branched. Sheaths glabrous ; blades 2'-8' long, l'-¥ 

 wide, scabrous above; spikes 2-3' long; spikelets about 

 1" long, equalled or exceeded by the downwardly barbed 

 bristles ; first scale less than one-half as long as the 

 spikelet, i-nerved ; second and third scales 5-7-nerved, 

 equalling the oval fourth one; palet of third scale 

 empty. 



A '-■out dwellings and in waste places, Nova Scotia and 

 Ontario to New Jersey, Missouri and Nebraska. Natural- 

 ized from Europe. Bristly or Brown Foxtail ; Rough 

 Bristle-grass. July-Sept. 



