252 PATAGONIAN EXPEDITIONS I BOTANY. 



10. H. VULGARE HEXASTICHON Linn. 



Flowers all hermaphrodite, 6-seriate. Spike erect, terete, awned ; the 

 awns rather broad, more or less divergent, twice as long as the spike, 

 which is 3-7 cm. long. Annual. 



(Cult, in N. Hemisphere) ; N. Patagon. (cult). 



59. ELYMUS Linn. Wild-rye. 



Culms tall; leaves flat; spikes dense having (i-)2-several-flowered 

 spikelets, mostly in pairs, sessile in alternate notches of the rachis, with 

 the awned glumes as an involucre. Grain adhering to the palea. (Fig. 

 in Brit. & Br. i, 230.) 



Species 30 in temperate regions. Distinguished from Hordeum by 

 having 2 or more flowers in each spikelet (except E. uniflorus]. 



KEY TO THE SPECIES. 

 A. Culm thick, spikes green-violet. 



b. 75 cm. Leaves smooth, becoming convolute. Spike 8 cm. Spikelets in 2's and 3*3; 



3-4-flowered. Floriglume short-awned. agropyroidcs. 



b2. To 1 80 cm. Leaves 7 mm. broad. Spike 15 cm. Spikelets i -flowered, 12 mm. long. 



Awn 17 mm. tiniflorus. 



A2. Culm leafy, sheathed to the top. 



/;. Leaf-blades rough beneath, complicate. Spike 18 cm. Spikelets 18 mm., 5-flowered. 



Awn of floriglume 25 mm. palena. 



b2. Culms 60 cm. Leaves short, glabrous. Spike linear-oblong. Spikelets 2-flowered. 



Floriglumes awned, hairy above. antarcticus. 



Ay,. Culms stout, 45 cm. Blades glabrous. Spike narrow, erect, long. Spikelets paired, 



3-flowered. Awn short. chubutcnsis. 



AA,. Culms slender. 



b. Glabrous, nearly a meter tall, with innovations. Sheaths and blades long. Spike 7 cm. 



Spikelets 3-flowered. ' Empty glumes short. Floriglume awned. albmvianus. 



b2. More or less puberulent. 



c. Culm 70 cm., sheathed half-way. Spike narrow ; spikelets in 2's, 3-flowered, 2 of them 



fertile ; leaves very narrow. Awn short. Icptostachys. 



C2. Culm 30 cm. Spike 8 cm.; spikelets 2-3-flowered, 1-2 fertile. Awn long. 



andinus. 



CT). Culm 75 cm., naked. Leaves rigid, broad, pubescent on upper surface. Spikes 7 

 cm. Spikelets 3 ; 2-flowered. Awn short. patagonicus. 



i. E. AGROPYROIDES Presl. 



Culm erect, 60-90 cm., as thick as a goose-quill. Leaves ultimately 

 convolute, smooth; ligules short, round. Spike 7-10 cm. long, rigid, 



