POACEAE. 55 



Glumes of fertile flowers dilated above the 



middle. 1. H. pusillum. 



Glumes not dilated. 



Glumes very scabrous. 2. H. nodosum. 



Glumes glabrous or minutely scabrous. 3. H. gussoneanum. 

 Glumes at least some of them ciliate. 4. H. murinum. 



1. H. pusilium Nutt. Annual; culms 1-4 dm. high; blades erect, 

 flat; spike erect, 2.5-7.5 cm. long, 10-14 mm, wide; the first glume 

 of the sterile lateral pairs of spikelets and both of the fertile spike- 

 let dilated above the base, attenuate into a slender awn 8-14 mm. 

 long; glumes very scabrous; floral glume not awned. 



In low heavy usually saline ground; Santa Catalina and San 

 Diego, 



2. H. nodosum L. Perennial; culms erect, slender, 2-6 dm. 

 high, sheaths glabrous; leaves often deflexed, flat, scabrous, 5-8 

 mm, wide; spike slender, compressed, usually nodding, 6-10 cm, 

 long, 8-10 mm, wide; rachis very brittle; lateral spikelets awnless, 

 staminate or neutral; flower of central spikelet sessile; empty glumes 

 not flattened or dilated above the base, all alike and subulate; 

 flowering glume including its awn 14-18 mm. long; awn usually 

 brownish or purplish. 



Frequent in moist places in all our valleys. 



3. H. gussoneanum Pari, Annual, rather glaucous ; culms more or 

 less decumbent at base, tufted, 1-2 dm, high; spikes 2-4 cm, long, 

 rather pale; lateral spikelets neutral or sometimes staminate, their 

 inner empty glumes narrowly flattened, 0.5 mm, wide; fertile flower 

 sessile. 



Occasional along the coast marshes. 



4. H. murinum L, Annual; culms tufted, decumbent at base, 

 2-5 dm, high; upper sheaths smooth, scarious on the margins, 

 often dilated, the lower pilose; leaves softly pubescent and scabrous; 

 spikes stout, compressed, 5-10 cm. long; central spikelet pedicelled; 

 empty glumes lanceolate, flat, ciliate; awns 18-24 mm. long; outer 

 empty glumes of lateral spikelets similar, the inner awn-like and 

 not ciliate; flowering glume about 12 mm, long, scabrous above; 

 awn 2-5 cm. long; flowering glumes of the lateral spikelets smaller; 

 awn 15-40 mm, long; palea ciliate on the keels, 



A very common and troublesome grass especially in pastured 

 land. Commonly called Fox-tail, 



41, ELYMUS L, Wild Rye. 



Mostly erect rather tall grasses with flat leaves and 

 closely flowered terminal spikes. Spikelets 2-6-flowered, 

 the uppermost imperfect, sessile, in 2's, rarely in 3's or 

 4's at the alternate notches of the continuous or articu- 

 late rachis; rachilla articulate above the empty glumes 

 and between the flowers. Empty glumes 2, nearly 

 equal, rigid, narrow, 1-3-nerved, acute or awn-pointed, 



