326 SLUMaCE-^ 



usually about twice as long as the spikelet. (Name from the 

 Greek lagos, a hare, and oura, a tail.) 



21. Polypogon (Beard-Grass). Spikelets densely crowded in a 

 spike-like or slightly branched panicle ; outer glumes ending in a 

 fine awn, a character which distinguishes the genus from Agrostis 

 (Name from the Greek polus, many, and fogon, a beard, in refer- 

 ence to the many long awns.) 



22. Gastridium (Nit-Grass). Distinguished from Agrostis by 

 the shining, enlarged base of the outer glumes. (Name from the 

 Greek gastridion, a little belly, in allusion to the base of the outer 

 glumes.) 



Tribe x. Avene^e. Spikelets with 2 or more flowers, the upper 

 often barren ; outer glumes as long as or longer than the flowers ; 

 flowering glume awned ; style short or none. 



23. Holcus (Soft Grass). Spikelets 2-flowered, numerous, in a 

 rather loose panicle ; outer glumes keeled, compressed ; I 

 flower hermaphrodite, its glume usually awaless ; upper flower male, 

 its glume with a shart awn ; axis of the spikelet without hairs. 

 (Name from the Greek holkos, drawing ; the ancients believed the 

 plant had the power of drawing thorns from the flesh.) 



24. Weingaertneria (Grey Hair-Grass). Similar to Aira. 

 Spikelets 2-flowered, awned ; awn straight, jointed in the middle, 

 slenderly club-shaped above, with a minute tuft of hairs at the 

 joint. (Named in compliment to Weingartner, a German who was 

 interested in the flora of Erfurt.) 



25. Aira (Hair-Grass). Differs from Arena in having much 

 smaller spikelets with usually only 2 flowers or rarely 1, the flower- 

 ing glumes are more membranous and do not project beyond the 

 outer, and the hair-like awn is shorter ; panicle loose. (Name from 

 the Greek aira, a kind of grass.) 



26. Trisetum (Yellow Oat). Spikelets numerous, small, in a 

 loose panicle. Differs chiefly from Avena in having a glabrous 

 ovary, while the fruit is not crested or furrowed. (Name from the 

 Latin tri, three, and seta, a bristle.) 



27. Avena (Oat). Spikelets rather large, 2-5 flowered, in a 

 loose panicle ; glumes membranous, at least at the top, the outer 

 lanceolate and tapering to a point, the flowering ones smaller, 

 2-cleft at the top and bearing a long twisted and bent awn on the 

 back ; axis of the spikelet hairy ; ovary hairy at the top ; fruit 

 crested and furrowed. {Avena is the old Latin name.) 



28. Arrhenatherum (False Oat.) Very much like Avena, but 

 differs in the lower of the 2 flowers of the spikelet containing 



