(36 



GR AMINES. 



to have been found only once, near Eden Vale railroad depot, Santa 

 Clara Co., in 1893, Davy. Mar. -June. 



36. POA L. Meadow-grass. 



Panicle usually open, sometimes dense and spikelike; branches in 

 pairs or £ whorls. Spikelets compressed, ovate or lanceolate, 2 to 6 

 or 9-flowered. Bracts unequal, keeled, awnless; lower 1 to 3-nerved; 

 upper larger, 3-nerved. Rachilla jointed below each bractlet. Bract- 

 let compressed-keeled, herbaceous or membranaceous, with the rachilla 

 and callus often clothed below with webby hairs or pubescent, espe- 

 cially on the dorsal and marginal nerve; apex hyaline; nerves 5 to 7, 

 the intermediate ones often faint; palea 2-tid, nerves 2, ciliate. Scales 

 acute. Stamens 3 or (rarely) 2 only Achene (in oursj mostly free 

 from the bractlet and palea, not furrowed. (Greek poe, grass or 

 herbage, especially that grown as forage for cattle, hence meadow- 

 grass.) 



Panicle open. 



Annual; stems 2 to 12 in. high LP. annva. 



Perennial; stems 12 to 36 in. high; rootstock distinctly stoloniferous and 



running 2. P. pratensis. 



Panicle contracted, more or less dense and spikelike; perennials; flowers often 

 dioecious or polygamo-dicecions 

 Rootstock running, Ions and slender; coast and sand-dunes . 3. P. Douglasii. 

 Rootstock tufted, not running. 

 Panicle 3 to 4V£ in. long; longest branches 1 to 2 in. long, spikelet- 

 bearing on the upper three-fourths; bracts and bractlets not ciliate on 



the keels; bunch-grass of dry hillsides 4. P. secunda. 



Panicle 2 to 3 in. long; longest branches less than 1 in. long, densely 

 spikelet-beanng almost to the base; bracts and bractlets scabrously 

 ciliate on the keels; moist sandy places on the coast cliffs. 



5. P. unilateral is. 



1. P. annua L. Walk-grass. Annual; stems compressed, weak, 

 geniculate below, 2 to 12 in. high; ligule 1 to 2 lines long; blades 

 bright green, glabrous, 1 to 2 lines wide; panicle often 1-sided, 1| 

 to 3.} in. long; branches single or in pairs, rarely in threes, 7 to 12 

 lines long; spikelets sessile or shortly pedicellate, 2 to 1\ lines long, 

 3 to 7-flowered; bractlets somewhat pilose below. Naturalized and 

 widely distributed: Monterey, 1846-47, Hartweg; Berkeley; etc. A 

 very troublesome weed on garden walks, hence the vernacular name; 

 our earliest-flowering grass. Nov. -Apr. 



2 P. pratensis L. Kentucky Blue-grass. Perennial; root- 

 stock distinctly running and stoloniferous; stem and sheaths smooth; 

 panicle open-pyramidal, 3 to 4 in. long; spikelets crowded at the 

 ends of the branches, almost sessile, 3 to 5-flowered; bractlet distinctly 

 5-nerved, webbed at the base. 



Introduced within our limits; frequently met with as an escape 

 from lawns: Berkeley. Apr.-May. 



3. P. Douglasii Nees. Sand-grass. Perennial; rootstock slen- 

 der, widely creeping; stems tufted, 8 in. high; panicle dense, 

 spike-like, ovoid, obtuse, 1 to 2 in. long; spikelets 3 to 6 lines long;, 

 flowers dioecious. 



