POACEAE. 21 



barbed; sheaths compressed, glabrous or pubescent; leaves 2-4 mm. 

 wide, scabrous, long acuminate, nearly equaling the culms, those 

 of the culms 15-45 mm. long; branches elongated, forming a com- 

 pact terminal inflorescence; spikes in pairs, about 25 mm. long, 

 loose, protruding from the sides of the scabrous sheaths; rachis 

 flexuous, the joints and pedicels pubescent with long spreading 

 silky hairs; outer glume about 3 mm. long; awn 12-18 mm. long, 

 scabrous; pedicelled spikelet reduced to a single scale or wanting. 

 {A. macrourus Michx.) 



Rubio and Eaton's Canyons, San Gabriel Mountains, Mc Clatchie. 



2. A. barbinoidis Lag. Culms erect, 4-10 dm. high, simple or 

 branched, glabrous, the nodes pubescent with silky hairs; sheaths 

 smooth; leaves 8-16 cm. long, 4-6 mm. broad, long-acuminate, 

 scabrous, glaucous; ligule hairy; spikes 25-35 mm. long, in an 

 exserted panicle, 5-10 cm, long; first glume of sessile spikelet ovate- 

 lanceolate, 4 mm. long, about equaling the terminal hairs of the 

 rachis joints, pubescent at base with long silky hairs, scabrous above; 

 awn 10-15 mm. long, spiral, bent, scabrous; pedicelled spikelet 

 reduced to a single narrow scale. 



Occasional on stony south slopes in the chaparral belt. Sepul- 

 veda Canyon and Cahuenga Pass, Santa jMonica Mountains; Tia 

 Juana, San Diego County; Gaviota, Santa Barbara County; Santa 

 Catalina Island. 



2. HOLCUS L. 



Annual or perennial grasses with long broad flat leaves 

 and terminal ample panicles. Spikelets in pairs at the 

 nodes, or in 3's at the ends of the branches, 1 sessile and 

 perfect, the lateral pedicelled, staminate or empty. 

 Sessile spikelet consisting of 4 glumes, the outer indurated 

 and shining, obscurely nerv^ed, the inner hyaline, the 

 fourth awned and subtending a small palea and perfect 

 flower, or palea wanting. Stamens 3. Styles distinct. 

 Grain free. 



1. H. halepensis L. (Johxsox-grass.) Culms erect, 9-15 dm. 

 high, simple or sometimes much branched, smooth; sheaths smooth; 

 leaves 2 dm. long or more, 7-25 mm. wide, long-acuminate; panicle 

 open, 15-45 cm. long; branches generally whorled, spreading, naked 

 towards the base; outer glumes of sessile spikelet 4-6 mm. long, 

 ovate-lanceolate, usually purplish, pubescent with long, appressed 

 hairs; awn 8-16 mm, long, more or less bent, sometimes wanting; 

 pedicelled spikelets of 4 glumes, the outer 2 about 6 mm, long, 

 membranous, the inner 2 shorter and narrower, sometimes with 

 staminate flowers, {Sorghum halepense Pers.) 



Becoming a troublesome grass in moist places along roadsides 

 and in fields. Especially common about Santa Ana. 



