WOOTON AND STANDLEY— FLORA OF NEW MEXICO. 75 



New Mexico: Tunitclia Mountains; Coolidge; Horsethief Canyon; Albuquerque; 

 Johnsons Mesa; Rio Pueblo; Trout Spring; Raton Mountains; Cliama; Sandia Moun- 

 tains; Fort Bayard; Mangas Springs; Socorro. Open slopes, in the Transition and 



Canadian zones. 



32. SPOROBOLUS R. Br. Dropseed. 



Annuals or perennials with small spikelets; spikelets 1-flowered, pedicellate, in 

 narrow or broad panicles; glumes rounded or slightly keeled, awnless, obscurely 

 nerved or nerveless, usually unequal; lemma equaling or exceeding the glumes, not 

 awned; palea as long as the lemma f)r longer; stamens 3; styles short, distinct. 



KEY TO THE SPECIES. 



Panicles narrow, spikelike. 



Plants tall, robust, 1 meter high, erect 1. S. giganteus. 



Plants low, slender, 60 cm. liigh or less, spreading or ascend- 

 ing 2. S. sirictus. 



Panicles branched and spreading. 



Annual, 20 cm. high or less 3. S. confusus. 



Perennials, usually more than 20 cm. high. 



Plants with long scaly rootstocks; glumes about equal. 

 Panicles 8 cm. long or less; stems rigid although slen- 

 der 4. S. auriculatus. 



Panicles 13 to 20 cm. long; stems weak, often elon- 

 gated 5. S. asperifolius. 



Plants without long scaly rootstocks; glumes very unequal. 

 Sheaths naked or sparingly ciliate in the throat. 

 Plants 30 cm. high or less; spikelets long-pedi- 

 cellate; sheaths villous 6. /S. texanus. 



Plants more than 50 cm. high; spikelets short- 

 pedicellate; sheaths not villous. 

 Plants less than 90 cm. high; panicles open, 

 with comparatively few spikelets; 



glumes nerved 7. S. airoides. 



Plants 100 to 180 cm. high; panicles rather 

 narrow, with very numerous spikelets; 



glumes not nerved 8. S. wrightii. 



Sheaths with a conspicuous tuft of hairs in the throat. 

 Sheatlis pubescent; leaf blades divergent; pani- 

 cles 8 cm. long or less; plants not more than 



30 cm. high, slender 9. S. nealleyi. 



Sheaths almost or quite glabrous; leaf blades not 



divergent; ])anicles 15 to 30 cm. long or 



more; plants mostly 60 cm. high or more, 



stout. 



Panicles exserted, spreading, sometimes 



somewhat nodding, the lower branches 



about as long as the upper ones 12. S. Jlexuosus. 



Panicles mostly included in the sheaths, 



rarely if at all spreading, the lower 



branches longer than the upper. 



Lemmas about equaling the glumes, 



acute to obtuse, less than 2 mm. 



long 10. S . cryptandrus. 



Lemmas much longer tlian glumes, long- 

 acuminate, 5 to 6 mm. long 11. S. asper. 



