GRAMINEAE (GRASS FAMILY) 55 



3. Sporobolus vaginaeflorus (Torr.) Wood, Classbook 775. 1861. Slender 

 caespitose annual, 2-4 dm. high: leaves 2 mm. wide or less, smooth and 

 glabrous beneath, scabrous and hairy near the base above, attenuate into a 

 slender involute point: panicles spike-like, terminal and axillary, about 2 cm. 

 long, mostly inclosed in the somewhat inflated leaf-sheaths: spikelets 3.5-4.5 

 mm. long: glumes unequal, acuminate; lemma scabrous, sparingly appressed- 

 pubescent, about as long as the second glume and equaling or slightly ex- 

 ceeded by the very acute palet. Infrequent; extending into our range from 

 the east. 



4. Sporobolus simplex Scribn. U. S. Dept. Agr. Div. Agrps. Bull. 11: 48. 

 1898. Very slender densely tufted annual, 5-30 cm. high, with short narrow 

 leaves, scape-like culms, and linear, few-flowered panicles 2 cm. long, exserted 

 nearly half their length: spikelets about 1.5-2 mm. long: glumes unequal, 

 1-nerved, obtuse and usually erose-dentate at summit; lemma 3-nerved, 

 acuminate and cuspidate. [S. filiformis (Thurb.) Scribn. U. S. Dept. Agr. Div. 

 Agros. Bull. 17: 173. 1899.} Extending into our range from the west. 



5. Sporobolus confusus (Fourn.) Vasey, Bull. Torr. Bot. Club 15: 293. 

 1888. Slender branching tufted annual, 8-20 cm. high, with capillary ovoid 

 or oblong panicles 8-15 cm. long: leaves flat, 1-4 cm. long, 1.5 mm. or less 

 wide: spikelets 1.25-1.5 mm. long: glumes obtuse, nearly equal, one half to 

 two thirds as long as the lemma, glabrous or pubescent; lemma obtuse, usually 



cumbent and branched base and diffuse panicles 6-10 cm. long: leaves numer- 

 ous, 2-8 cm. long, 2-3 mm. wide at base, acuminate, strict, often erect, flat, 

 glabrous, smooth beneath, very rough above: spikelets 1.5 mm. long, occa- 

 sionally 2-3-flowered: glumes subequal, acute, glabrous, sparingly scabrous; 

 lemma obtuse or acute, glabrous, somewhat exceeding the second glume. 

 Throughout the western half of North America. 



7. Sporobolus airoides Torr. Pac. R. R. Rept. 7 a : 21. 1856. Stout coarse 

 and rigid densely caespitose perennial, 3-9 dm. high, with long, narrow leaves 

 and open spreading pyramidal panicles 10-25 cm. long: leaves smooth be- 

 neath, scabrous above and sometimes sparingly hairy near the base, 1-3 mm. 

 wide at the base, attenuate into a long slender involute point ; the basal about 

 one half as long as the culm; the upper culm leaves 5-12 cm. long: spikelets 

 1.5-2 mm. long: glumes acute, glabrous, nerveless, unequal, the first about 

 half as long as the second; lemma equaling the second glume and the palet. 

 From Mexico to Dakota and west to the Pacific States. 



8. Sporobolus cryptandrus (Torr.) Gray, Man. f>76. 1848. Erect glabrous 

 perennial, 4-7 dm. high: sheaths with a dense pilose ring at the summit; 

 leaves 7-15 cm. long, 2-A mm. wide, flat, scabrous above, long-acuminate: 

 panicles 12-20 cm. long, spreading in flower, usually narrow, more or less in- 

 closed in the upper sheath: spikelets 2-2.5 mm. long: glumes acute, glabrous, 

 the first one half as long as the second, which is about as long as the lemma. 

 Across the continent northward, and south in the interior to Mexico. 



9. Sporobolus argutus (Xees) Kunth, Enum. 1: 215. 1833. Caespitose 

 perennial, 2-4 dm. high, with flat leaves and open panicles 3-8 cm. long, the 

 branches verticillate and spreading in flower: leaves 25-50 mm. long, 2-4 mm. 

 wide at the base, acuminate, smooth and glabrous beneath, scabrous and 

 often sparingly hairy at the base above: spikelets 1.5 mm. long: glumes smooth 

 and glabrous, the first rounded or obtuse, one fourth as long as the acute 

 second one; lemma about equaling the second glume, acute. Colorado and 

 southward. 



10. Sporobolus heterolepis Gray, Man. 576. 1848. Rather stout erect 

 caespitose perennial 3-9 dm. high: leaves involute-setaceous, glabrous, the 

 margins and upper part of the midrib very rough; the basal about three 

 fourths as long as the culm, occasionally equaling it; those of the culm 

 shorter: panicle loose and open, 7-25 cm. long: spikelets 4-5.5 mm. long: 

 glumes very unequal, sharply acuminate-pointed, the first subulate, about 



