128 



POACEAE 



10. Aristida fendleriana Steud. 

 Fendler's Aristida. Fig. 273. 



Aristida fendleriana Steud. Syn. PI. Glum. 1: 420. 

 1854. 



Perennial ; culms densely cespitose, erect, 

 usually less than 30 cm. tall ; blades crowded 

 at base of culms, formmg a curly tuft, involute, 

 arcuate, sharp-pointed, pilose at base, usually 

 3.2-5 cm. long, sometimes longer : panicle 

 narrow, 5-10 cm. long, bearing a few, mostly 

 short-pediceled loosely arranged, more or less 

 appressed spikelets ; glumes unequal, smooth, 

 awnless, 1-nerved, the first about 6 mm. long, 

 the second 10-12 mm. long, scaberulous and 

 slightly narrowed above; callus minutely 

 pubescent, 1 mm. long; awns equal, about 2-3 

 cm. long, ascending. 



Deserts ami plains, southern California (San Ber- 

 nardino Mountains, Parish) to Texas. June. Type 

 locality: New Mexico. 



17. STIPA L. Sp. PI. 78. 1753. 



Spikelets 1-flowered, articulate above the glumes, the articulation oblique, leaving a 

 bearded sharp-pointed callus attached to the base of the floret ; glumes membranaceous, 

 often papery, acute, acuminate, or even aristate, usually long and narrow ; lemma narrow, 

 terete, firm or indurate, strongly convolute, terminating in a usually bent and twisted 

 prominent persistent awn ; palea inclosed in the convolute lemma. Perennial grasses with 

 usually convolute blades and narrow panicles. [Greek, tow, referring to the feathery awns of 

 some species.] 



Species about 100 in the temperate regions of the world, especially on plains and steppes. Type species, 

 Stipa pcnnata L. 



1. 



2. 



3. 



4. 

 5. 



Awn plumose. 



Awn with 1 bend, very jilumose below the bend. 

 Awn with 2 bends, plumose to second bend. 



Ligule 3-6 mm. long. 

 Ligule very short. 



Sheaths pubescent. 

 Sheaths glabrous. 



Blades involute, mostly basal. 



Blades fiat, tardily involute, scattered. 



Awn more or less scabrous, but not plumose. 



Lemma clothed with copious hairs, 4 mm. long. 



Awn with 2 bends; plants 1 meter or more tall. 



Awn with usually 1 bend; plant 30—50 cm. tall. 

 Lemma more or less hairy, the hairs not over 1 mm. long. 



Panicle open, the branches naked below, more or less spreading. 



Upper glume 5-nerved; lower glume 3- or 5-nerved. 

 L'pjjer and lower glumes 3-nerved. 



Ligule evident; terminal segment of awn mostly 4 cm. or more long. 9. 



Ligule very short; terminal segment of awn mostly less than 2 cm. long. 10. 



Panicle narrow, the branches erect. 



.Sheaths pubescent; culms pubescent below the nodes. 

 Sheaths glabrous. 



Glumes 15-20 mm. long; blades as much as 7 mm. wide. 

 Glumes 10 mm. or less long. 

 Sheaths hairy at the throat. 

 Sheaths not hairy at the throat. 



Glumes broad, usually 5-nerved; fruit fusiform. 

 Glumes narrow, 3-nerved. 



Blades slender, involute: lemma scarcely 5 mm. long. 

 Blades flat; lemma usually more than 5 mm. long. 



Lemma about 7 mm. long; culms usually 1-1.5 meters tall. 16. 

 Lemma 5-6 mm. long; culms usually less than 1 meter tall. 



17. 



S. steciosa. 



S. thurbcriana. 



S. elineri. 



S. occidentalis. 

 S. calif or nica. 



S. coronata. 

 S. parishii. 



8. 6". comata. 



S. pulchra. 

 S. lepida. 



11. 



i: 



13. 



14. 



15. 



.S". tviHiainsii. 



S. stiilmanii. 



S. laseyi. 



S. lemtnoni. 

 S. lettermaiii. 



S. nelsoni. 



S. minor. 



