POACEAE. 45 



Annuals. 



Sheaths smooth. 1. P. annua. 



Sheaths scabrous. 2. P. higelovii. 



Perennials. 



Sheaths smooth. 3. P. pratensis. 



Sheaths scabrous. 



Floral glume villous on keel and marginal 



nerves. 4. P. fend'eriana. 



Floral glume not villous, but pubescent 



below. 5. P. scahrella. 



1. P. annua L. Annual; culms weak, compressed, 5-30 cm. 

 long, decumbent; ligule 2-3 mm. long; blades of the sterile shoots 

 |-f as long as the culms; culm leaves 3, flat; panicle subsecund, 

 ovoid, 2-5 cm, long, its branches usually in pairs, the longest 2.5 

 cm. long, bearing spikelets above the middle; spikelets nearly sessile, 

 3-7-flowered, 4-6 mm. long; empty glumes compressed, about 2.5 

 mm. long; flowering glume ovate, smooth, erose at apex, 2.8-3.1 

 mm. long, with soft hairs on the keel and lower part of the lateral 

 nerves; palea 2.5-2.8 mm. long, ciliate or pubescent on the keels. 



Common in moist places in all our valleys. Native of Europe. 



2. P. bigelovii Vasey & Scribn. Annual, with erect slender 

 culms 1-4 dm. high; sheaths scabrous; panicle narrow, 7-15 cm. long, 

 the branches short and appressed; spikelets ovate, 6 mm. long; 

 empty glumes acuminate, 3-nerved, 4 mm. long; floral glume 4 mm. 

 long, webbed at base, conspicuously pilose on the lower part of the 

 lateral nerves and keel, and villous between on the lower part of 

 back. 



Los Angeles, Davidson, according to Hitchcock. 



3. P. pratensis L. (Kentucky Blue-grass.) Perennial; culms 

 terete, glabrous, from running rootstocks, 3-6 dm. high; sheaths 

 smooth; ligule truncate, 1.5 mm. long; leaves of the sterile shoots 

 flat, abruptly concave-pointed, those of the culms 3, smooth or 

 scabrous; panicle usually rather open pyramidal, its branches in 

 half whorls of 3-6, densely flowered on the upper half; spikelets 3-6- 

 flowered, 4-7 mm. long; empty glumes acute, scabrous on the keels, 

 first 2.5-3 mm. long, second 3-3.5 mm. long; flowering glume webbed 

 at the base, scabrous toward the apex, pubescent on the marginal 

 nerves and on the keel below; palea linear, 2.5-3 mm. long, scabrous 

 on the keels. 



Frequent in lawns and occasional in mountain meadows. Bear 

 Valley; Cuyamaca. 



4. P. fendleriana (Steud.) Vasey. Perennial; culms tufted, 

 3-7 dm. high, usually dioecious; leaves of sterile shoots usually flat, 

 6-10 cm. long, 2 mm. wide, culm leaves 2-3, conduplicate, 1-10 cm. 

 long; ligule 3-5 mm. long; panicle spike-like, 8-12 cm. long, its 

 branches in 2's or 3's, flower-bearing on the upper half; spikelets 

 ovate-lanceolate, flattish, often tinged with purple, 3-7-flowered; 

 empty glumes nearly equal, compressed, 4-5 mm. long; flowering 

 glume oblong, 4-5 mm. long, often denticulate at the apex, scabrous; 

 palea lanceolate, scabrous, shorter than or equaling its glume. 



Frequent on dry open hillsides in the chaparral belt. 



