248 PATAGONIAN EXPEDITIONS I BOTANY. 



A. REPENS PUNGENS Brongn. 



Glumes and palece pubescent ; spikelets with up to 6 flowers. Plant 

 more stout than the northern form. 

 Patagonia. 



58. HORDEUM Linn. Barley. 



Erect annuals, rarely perennials, with flat leaves, and terminal spikes 

 having i -flowered spikelets inserted in triplets, or 2, or 6, at each joint 

 of the rachis ; the mid-one of each triplet being sessile, and the lateral 

 pair with short pedicels and imperfect flowers. Rachilla articulated below 

 the flowers, and produced above them as long awns or as glumes. 

 Empty glumes rigid, often awn-like, and the six belonging to each triplet 

 forming an involucre. Floral glume strong-awned ; palea nearly as long. 

 Styles short ; grain adherent to the palea. 



Species 16, in Eurasia, N. Afr. and Amer. 



KEY TO THE SPECIES. 



A. Spikelets distichous, 2-ranked in the compressed, subcurved spike. Of the paired spikelets 



one is perfect and one neutral. Floriglumes awnless. andicolum. 



A2. Tristichous, spikelets in triplets. 



b. Culm creeping. Leaves hairy. Glumes all setaceous and scabrid. Mid-floriglume long- 



awned. Lateral spikelets male. comosiim. 



b2. Spike cylindrical, slender. Leaves short, convolute. Glumes scabrid ; mid-floriglume 



long-awned ; lateral spikelets neuter. chilense. 



b$. Spikes breaking into segments when ripe. 



c. Hairy. Coarse annual. Leaf-blades 5 cm. long. Joints of rachis 3 mm. Spike 

 partly sheathed. Mid and lateral floriglumes dorsally flat, scabrous above. 



murinum. 



c2. Glabrous. Joints of rachis less than 2 mm. 

 d. Culm basally geniculate. 



e. Culm 20 cm. Leaves narrow. Spike rigid, scarcely protruding. Empty 

 glumes smooth. Lateral spikelets short-awned. maritimum. 



2. Culm 50 cm. Leaf-blades 1 1 cm. long. Empty glumes rough. Central 



floriglume short-awned. pratense. 



d2. Culm 40 cm. Spike 6 cm., with a slender rachis, easily breaking. Central flori- 

 glume and lateral empty glumes long-capillary. jubatum. 



A$. Spikelets hexastichous, in six ranks, and all perfect. Erect annual, 70 cm. tall. Spikes 

 IO cm., compressed. Awns often 15 cm. Floriglume adhering to the grain. 



hexastichon. 



i. H. ANDICOLUM Gris. 



Cespitose perennial, with fibrous rhizome. C^tlms 20-30 cm. high ; 

 leaves plane, acuminate, glabrous. Spike linear, compressed, slightly 



