378 



Bulletin No. 205 



[March, 



tooth on each side, and the midncrve and hitcral nerves are densely 

 hairy for about half their length. The leaves are flat, long, and nar- 

 row; the ligule is a fringe of short hairs. 



^. 



208 



209 



210 



211 



Figs. 208-211. — 208, T. flamis, inflorescence; 209, T. flavus, spikelet; 210, 

 T. purpurea, inflorescence; 211, T. purpurea, spikelet 



Tridens flavus (L.) Hitchc. 

 Tall Redtop (Figs. 208 and 209) 



Poa seslerioides, Michaux '03, 68. Tricuspis seslerioides, Lapham '57, 546, 

 574 (Plate 2, Fig. 7); Patterson '76, 50; Flagg '78, 281; Brendel '87, 63; 

 Gleason '07, 182. Tridens flavus, Gleason 'lU, 149. 



Culms slightly flattened, smooth, 3 to 6 feet tall ; sheaths hairy at 

 the throat ; blades rough, 4 to 12 inches long, 6 to 12 mm. wide, nar- 

 rowed to a sharp point at tip ; panicle 6 to 18 inches long, the long 

 branches drooping, usually deep purple, sometimes reddish ; spikelets 

 7 to 8 mm. long. 



This species is very striking and handsome with its large purple 

 panicles. It has a yellow form, but no Illinois specimens of this have 

 been seen. When in bloom, the panicle, axis, and branches are covered 

 with a viscid, oily substance, which makes them very sticky. This 

 species was one of the grasses of the original prairie, and is still quite 

 abundant thruout the state. 



