332 POACEiE. 



whorls of 4-6, the longest 2 cm. long, bearing 6-14 spikelets below 

 the middle. Empty glumes equal or subequal, ovate when spread, 

 abruptly acute, scabrid on the keel, 2 mm. long, a little more or 

 less; floral glume broadly oval, truncate, a little shorter than the 

 empty glumes; palea broad, 0.7 mm. long. 



Mexico, Pringle 4251, near brooks, at an altitude of 12,000 feet; 

 also found in Quito, S. A. 



21. A. ALBA L. Sp. PI. 63 (1753). Red Top. Creeping 

 Bent. Fiorin. 



Culms 40-100 cm. high, often decumbent at the base from 

 perennial rootstocks making a close turf. Sheaths smooth, about 

 as long as the internodes; ligule oblong or linear, 3-5 mm. long; 

 blades 5-7, flat, smooth or roughened, 8-18 cm. long, 3-7 mm. wide. 

 Panicle exserted, oblong, green, purple or brown, 12-20 cm. long, 

 spreading when in flower and contracting afterwards ; rays rough, 

 the lower in half- whorls of 8-30, some very short, others sometimes 

 7 cm. long, flower-bearing along the upper two-thirds. Spikelets 

 2-2.5 mm. long; first glume exceeding the second but very little 

 or none; floral glume truncate, 1.5-2 mm. long or a little less, 3-5- 

 nerved, rarely with a short awn; palea one-third to two-thirds as 

 long as its glume. 



Vermont, Pringle; Massachusetts, C. E. Faxon, Beal 72, Siur- 

 tevavant; Ontario, Fowler; Pennsylvania, Scrihner for. U. S. Dept. 

 Agricul. 411; Michigan, Clark 692, G93, Cooley, Beal 73, 74, 75, 

 Farwell^ Prentiss 130; Minnesota, Bailey B 127, Holzinger; Illi- 

 nois, Sandberg 35; Colorado, Cassidy; Wyoming, Buffum C 51; 

 Montana, Anderso7i 72; District of Columbia, McCarthy. 



No. 4485 of Pringle's Plants of Mexico in 1893, labelled A. 

 SrJiiedeana Trin., seems to belong here. 



A very variable grass, often abundant on river bottoms and 

 marshes. In Michigan it is the only grass known among farmers 

 as "Red Top." In Pennsylvania it is known as ''Herd's Grass." 

 It is a native of Europe. 



" Its different forms have given grounds for over 30 nominal 

 species. A. alha has an elongated acute ligule, and the panicle con- 

 tracted after flowering; the form once known as the species A. vul- 



