54 GRAMINEAE (GRASS FAMILY) 



2. Alopecurus occidentals Scribn. Bot. Gaz. 11: 170. 1886. Erect, rather 

 slender, 6-9 dm. high: leaves flat, 5-15 cm. long, 4-7 mm. wide: spikes 2-3 cm. 

 long, 8-15 mm. broad: spikelets 3.5-4.5 mm. long, compressed: glumes sub- 

 equal, acute, silky-hairy on the keels and pilose on the sides; lemma a little 

 shorter than the glumes, the margins connate to near the middle, pubescent 

 near the apex; awn inserted below the middle, about 6 mm. long. In the 

 high mountains. 



24. PHIPPSIA R. Br. 



Low tufted perennial, with flat leaves and slender few-flowered panicles. 

 Spikelets 1-flowered. Glumes minute, the first often wanting; lemma thin- 

 membranous, keeled; palet somewhat shorter, 2-keeled. Stamen 1, rarely 

 2 or 3. Styles short, distinct; stigmas plumose. Grain oblong, inclosed in 

 the lemma and palet, which readily split and allow it to drop out. 



1. Phippsia algida (Soland.) R. Br. Suppl. App. Parry's Voy. 275. 1824. 

 Smooth and glabrous throughout, 2-10 cm. high: leaves narrow and soft, 

 25 mm. in length or less, 0.5-2 mm. wide, obtuse: panicles contracted, simple, 

 6-35 mm. long, scarcely exceeding the leaves: spikelets 1-1.5 mm. long: 

 glumes minute, unequal, acutish; lemma broad, 1-nerved, obtuse or sub- 

 truncate and somewhat erose, the palet about two thirds as long, broad, 

 2-keeled, erose-truncate. High mountain peaks of Colorado, and probably 

 of Wyoming; in the arctic regions generally. 



25. SPOROBOLUS R. Br. DROP-SEED GRASS. RUSH GRASS 



Perennials or rarely annuals, with flat or convolute leaves and open or con- 

 tracted panicles. Spikelets generally small, 1-flowered, occasionally 2-3- 

 flowered. Glumes of the 1-flowered spikelets 2, membranous, unequal, the 

 first somewhat shorter; lemma equaling or longer than the glumes; palet 

 2-nerved. Stamens 2-3. Styles very short, distinct; stigmas plumose. 

 Grain free, and often early deciduous. 



Panicle contracted, spike-like. 



Plant only 2-4 cm. high 1. S. Wolfii. 



Plant more than 4 cm. high. 



Lemmas 3-4.5 mm. long 2. S. brevifolius. 



Lemmas less than 3 mm. long. 



Panicle more or less inclosed in inflated leaf-sheaths . . 3. S. vaginaeflorus. 

 Panicle exserted . . . . . . . . 4. S. simplex. 



Panicle open, at least during anthesis. 

 First glume about equaling the second. 



Annual . . . . . . . . . . 5. S. confusus. 



Perennial . . . . . . . . . 6. S. asperifolius. 



First empty glume one half as long as the second. 

 Spikelets 2.5 mm. long or less. 



Glumes both nerveless . . . . . 7. S. airoides. 



Glumes one or both 1-nerved 



Panicle 12-20 cm. long 

 Panicle 3-8 cm. long 

 Spikelets 4-5.5 mm. long 



8. S. cryptandrus. 

 . 9. S. argutus. 

 . 10. S. heterolepis. 



1. Sporobolus Wolfii Vasey, Bull. Torr. Club 10: 52. 1883. Slender an- 

 nual, branching at base, 2-4 cm. high: leaves mostly radical, flat or involute, 

 3-12 mm. long: panicles spike-like, simple, few-flowered, terminal and lateral; 

 the lateral ones partly inclosed in the loose sheaths: spikelets about 1 mm. 

 long: glumes oval, subequal, 0.7 mm. long; lemma about 1 mm. long. Twin 

 Lakes, Colorado. 



2. Sporobolus brevifolius (Nutt.) Scribn. Mem. Torr. Bot. Club 5: 39. 

 1895. Smooth glabrous perennial: culms 15-45 cm. high, arising from a 

 horizontal rootstock, branching at base, slender, erect or geniculate: leaves 

 1-5 cm. long, involute-setaceous: panicle 1-7 cm. long, linear, its branches 

 6-12 mm. long, erect or appressed: spikelets 2.5-3 mm. long: glumes unequal, 

 less than half as long as the lemma, obtuse or acute, scabrous on the keel and 

 at the apex; lemma long-acuminate, somewhat cuspidate, scabrous toward 

 the apex. Throughout our range. 



