280 



MISC. PUBLICATION 200, U. S. DEPT. OF AGRICULTURE 



the lemma; stamen 1. Low annual, 

 with slender cylindric spikes. Type 

 species, Scribneria bolanderi. Named 

 for F. Lamson-Scribner. 



1. Scribneria bolanderi (Thurb.) 

 Hack. (Fig. 375.) Culms branching at 

 base, erect or ascending, 7 to 30 cm. 

 tall; foliage scant, the blades subfili- 

 form; ligule about 3 mm. long; spike 



about 1 mm. thick, usually one-third 

 to half the entire height of the plant, 

 the internodes 4 to 6 mm. long; spike- 

 lets about 7 mm. long; lemmas pu- 

 bescent at base, the awn erect, 2 to 4 

 mm. long. — Sandy or sterile 

 ground, in the mountains, Washing- 

 ton to California; rare or overlooked, 

 very inconspicuous. 



TRIBE 4. AVENEAE 



54. SCHISMUS Beauv. 



Spikelets several-flowered, the rachilla disarticulating above the glumes and 

 between the florets; glumes subequal, longer than the first floret, usually as 

 long as the spikelet, with white membranaceous margins; lemmas broad, 

 rounded on the back, several-nerved, pilose along the lower part of the margin, 

 the summit hyaline, bidentate; palea broad, hyaline, the nerves at the margin. 

 Low tufted annuals with filiform blades and small panicles, the slender pedicels 

 finally disarticulating at the base and falling with the spikelet or with the 

 glumes. Type species, Schismus marginatus Beauv. (S. barbatus). Name from 

 Greek, schismos, a splitting, referring to the bidentate lemmas. This genus has 

 usually been placed in the tribe Festuceae, but its characters place it more 

 naturally in the tribe Aveneae. 



Glumes 4 to 5 mm. long; lemmas about 2 mm. long, rounded and emarginate at apex; palea 

 rounded, as long as the lemma. 1. S. barbatus. 



Glumes 5 to 6 mm. long; lemmas 2.5 to 3 mm. long, the apex with 2 acute hyaline lobes; 

 palea acute, shorter than the lemma 2. S. arabicus. 



1. Schismus barbatus (L.) Thell. 

 (Fig. 376.) Culms tufted, erect to 

 prostrate-spreading, 5 to 35 cm. tall; 

 blades usually less than 10 cm. long; 

 panicle oval to linear, 1 to 5 cm. long, 

 usually rather dense, pale or purplish ; 

 spikelets about 5-nov»ered; glumes 4 

 to 5 mm. long, shorter than the spike- 

 let, 5- to 7-nerved, acute; lemmas 

 about 2 mm. long, 9-nerved, the mar- 

 gin appressed-pilose on the lower half, 

 the teeth minute, sometimes with a 

 mucro between, the rachilla joints 

 slender, flexuous; palea concave, as 

 broad as the lemma and about as 

 long. O — Open ground in yards, 

 along roadsides, and in dry river beds; 

 Utah to California and southern Ari- 

 zona; Argentina, Chile. Introduced 

 from the Mediterranean region; India 

 to South Africa. 



2. Schismus arabicus Nees. (Fig. 

 377.) Resembling *S. barbatus, culms 

 widely spreading, the spikelets a little 

 larger, 5- to 7-flowered; lemmas 2.5 to 



Figure 376. — Schismus barbatus. Plant, X X A\ spike- 

 let and florets, X 5. (Peebles and Harrison 846, 

 Ariz.) 



