344 GRASS FAMILY 



Alopecurus Linne 1753 Foxtail 



(Gr. alopex, fox, oiira, tail, from the spike) 



PI. 46, fig. 18. 



Spikelets 1 -flowered, flattened, in a narrow spike; glumes acute or short- 

 awned, flattened and keeled ; lemma obtuse, 3-nerved, awned on the back, 

 palet hyaline, acute or none ; annual or perennial. 



1. Spikes 1-4 in. long, 4-8 mm. wide A. geniculdtus 



2. Spikes 1-1.5 in. long, 8-15 mm. wide A.alpinus 



Andropogon Linne 1753 Bluestem, Bunch Grass 



(Gr. aner, andros, man, pogon, beard, from the hairy axis) 



PI. 46, fig. 34, 35. 



Spikelets in pairs at each joint of the hairy axis of the terminal and 

 axillary spikes, one spikelet sessile and perfect, with 2 glumes, 2 lemmas, 

 the inner awned, and a palet ; the other spikelet with a stalk, either stam- 

 inate, empty, or represented by a single scale ; tall perennials. 



1. Spikes solitary, 1-2 in. long, distant; stems 2-4 



ft. high, usually densely clustered ; awn of the 



glume 10-12 mm. long A. scopdrius 



2. Spikes 2 or more in a cluster ; stems 2-6 ft. high 



a. Spikes 2-5 together in an umbel-like cluster; 



stems 3-6 ft. high 



(1) Hairs as long as the stalk, or longer; awn 



4-10 mm. long or wanting A. Hdllii 



(2) Hairs less than half the length of the stalk ; 



awn 10-15 mm. long A. furcdtus 



b. Spikes several in a short panicle ; stems 1-4 



ft. high; awn 8-16 mm. long A. torreydnus 



Aristida Linne 1753 Aristida, Wire Grass 



(Lat. arista, awn) 



PI. 46, fig. 17. 



Spikelets 1-flowered, in narrow panicles or spikes ; glumes keeled ; lem- 

 ma stiff and folded, bearing- 3 awns, sometimes united at base, the 2 lateral 

 awns sometimes much reduced or wanting, palet 2-nerved ; annual or peren- 

 nial, often with needle-like leaves. 



1. Glumes nearly equal, the upper with an awn 4-8 



mm. long A. oligdntha 



