MANUAL OF THE GRASSES OF THE UNITED STATES 437 



89. ORYZOPSIS Michx. Ricegrass 



Spikelets 1-flowered, disarticulating above the glumes; glumes about equal, 

 obtuse to acuminate; lemma indurate, usually about as long as the glumes, 

 broad, oval or oblong, nearly terete, usually pubescent, with a short, blunt, 

 oblique callus, and a short deciduous, sometimes bent and twisted awn; 

 palea enclosed by the edges of the lemma. Mostly slender perennials, with 

 flat or often involute blades and terminal narrow or open panicles. Type 

 species, Oryzopsis asperifolia. Name from oruza, rice, and opsis, appearance, 

 alluding to a fancied resemblance to rice. 



Nearly all the species are highly palatable to stock, but are usually not in 

 sufficient abundance to be of importance, except 0. hymenoides (Indian rice- 

 grass), which is common in the arid and semiarid regions of the West and 

 furnishes much feed. The seed has been used for food by the Indians. Locally 

 important may be 0. micrantha in the Black Hills region and 0. kingii in the 

 high Sierras. 0. miliacea is cultivated for forage in California. 



As the result of study of several species of Oryzopsis and Stipa, Johnson 

 and Rogler 13 conclude that the types of Oryzopsis cadnca and 0. bloomeri are 

 hybrids between 0. hymenoides and Stipa viridula and 0. hymenoides and S. 

 occidentalism respectively. For these the generic name Stiporyzopsis is proposed. 

 Other hybrids between 0. hymenoides and six other species of Stipa — S. elmeri, 

 S. thurberiana, S. calif ornica, S. scribneri, S. robusta, and S. columbiana — are 

 described, but not transferred to Stiporyzopsis. 



Lemma smooth (rarely pubescent in 0. micrantha). 

 Blades flat, 5 mm. wide or more. Spikelets numerous, about 3 mm. long. 



1. O. MILIACEA. 



Blades more or less involute, less than 2 mm. wide. 



Panicle branches spreading or reflexed; fruit about 2 mm. long, pale. 



2. O. MICRANTHA. 



Panicle branches ascending or appressed; fruit about 4 mm. long, dark brown. 



3. O. HENDERSONI. 



Lemma pubescent. 



Pubescence on lemma long and silky. 



Panicle branches and the capillary pedicels divaricately spreading. 



12. O. HYMENOIDES. 



Panicle branches and pedicels erect or ascending. 



Awn 6 mm. long; culms usually not more than 30 cm. tall 11. O. webberi. 



Awn 12 mm. long; culms 30 to 60 cm. tall. 10. O. bloomeri. 



Pubescence on lemma short, appressed. 



Spikelets, excluding awn, 6 to 9 mm. long; blades flat. 



Basal blades elongate, uppermost not more than 1 cm. long.... 8. O. asperifolia. 



Basal blades reduced, upper elongate 9. O. racemosa. 



Spikelets, excluding awn, 5 mm. long or less; blades involute or subinvolute. 

 Panicle branches erect or appressed. 



Blades and panicle stiff, erect; awns about 5 mm. long 4. O. exigua. 



Blades flexuous, the panicle somewhat so; awns at least 10 mm. long. 



7. O. KINGII. 



Panicle branches loosely ascending or spreading. 



Awn not more than 2 mm. long, straight or nearly so 5. O. pungens. 



Awn 10 to 20 mm. long, weakly twice-geniculate 6. O. canadensis. 



1. Oryzopsis miliacea (L.) Benth. 



and Hook, ex Aschers. and Schweinf. blades flat, 8 to 10 mm. wide; panicle 



Smilo grass. (Fig. 625.) Culms rela- 15 to 30 cm. long, loose, the branches 



tively stout, sometimes branching, spreading with numerous short-pedi- 



erect from a decumbent base, 60 to celed spikelets beyond the middle; 



150 cm. tall; ligule about 2 mm. long; glumes acuminate, 3 mm. long; lem- 



« Amer. Jour. Bot. 30: 49-56. f. 1-40. 1943; johnson, b. l., Amer. Jour. Bot. 32: 599-608. f. 1-71. 1945; 

 Bot. Gaz. 107: 1-32. 1945. 



