388 



POACEiE. 



more properly) is much reduced. Herbarium specimens from Eu- 

 rope, when dry, show 3 corms, in all 2.5-3 cm. long, 1-1.5 cm. 

 wide. 



80. (164). Tristachya Nees, Agrost. Bras. 458. (1829). Mo7io- 

 imjon Presl. Eel. Ifenk. 1:324 (1830). 



Spikelets 2-fiowered, collected in threes, sessile or raised on 

 short subequal pedicels at the ends of the branches of the panicles; 

 rachilla hairy, not extending above the upper flower, the lower one 

 male, the upper perfect or female. Empty glumes 2, slightly un- 

 equal, persistent, membranous, awnless, glabrous or the outer cili- 

 ate, floral glume of the lower spikelet membranous, awnless, tliat of 

 the upjier bifid bearing a long twisted awn between the teeth of the 

 apex; palea enclosed by the floral glume, membranous, 2-nerved. 

 Lodicules 2. Stamens 2 or 3. Styles distinct, very slender. Grain 

 oblong or linear, enclosed, but not adherent. 



Perennials or rarely annuals, usually firm, blades flat or convo- 

 lute. Panicle loose, spikelets few and 

 large, erect or nodding or smaller and 

 more numerous. 



There are eight species, two American; 

 the others are found in tropical Africa, 

 Australia, or western Asia. 



Here the lower flower is staminate as 

 in Arrhenatherum; spikelets always 3 to- 

 gether, sessile or equally pedicellate, the 

 long twisted awn of the floral glume ter- 

 minal and between two lobes or the awns 

 straight. 



1. T. leiostachya Nees, Agrost. Bras. 



459 (1829). T. Mexicana Kunth, Enum. 



PI. 1:308 (1833). Monopogon avenaceus 



Presl, Pel. Hsenk. 1:325, if. 44 (1830). 



An erect glabrous perennial, 30-40 cm. high. Leaf-blades 



fiat, 5 mm. wide, the upper blade 8 cm. long. Panicle simple, 



narrow, 20 cm. long. Eui])ty glumes with three prominent nerves, 



tips scarious, first 2.5 cm. long, second 3 cm. long, 3 mm. wide; 



A'' ^ 



Fig. 67. — Trktachya Mexi 

 cana. A. spiUt-lel; a, 

 floret. (liicbardsou.) 



