Genus 34. 



GRASS FAMILY. 



189 



14. Muhlenbergia pungens Thurb. 

 Prairie Dropseed. Fig. 452. 



Muhlenbergia pungens Thurb. Proc. Acad. Phila. 

 1863: 78. 1863. 



Culms 6'-is' tall from a creeping rootstock, 

 erect from a decumbent branching base, rigid, 

 minutely pubescent. Sheaths overlapping, 

 crowded at the base of the culm, scabrous ; 

 ligule a ring of soft silky hairs; blades i'-2' 

 long, involute-setaceous, rigid, scabrous; pan- 

 icle 3'-6' in length, open, the branches 2'-2i' 

 long, single, distant, much divided from near 

 the base, the divisions apparently fascicled ; 

 spikelets on long pedicels, which are clavate- 

 thickened at the apex; outer scales, when ma- 

 ture, equalling or often shorter than the body 

 of the third one, scabrous, especially on the 

 keel ; third scale, when mature, i"-i" long, sca- 

 brous, the awn shorter than its body. 



On prairies, Nebraska to Utah, south to Texas 

 and Arizona. Blow-out-grass. Aug.-Sept. 



15. Muhlenbergia capillaris (Lam.) Trin. Long-awned Hair-grass. Fig. 453. 



Stipa capillaris Lam. Tabl. Encycl. 1 : 158. 1791. 



Muhlenbergia capillaris Trin. Unifl. 191. 1824. 



Glabrous, culms i4°-4° tall, erect, simple, smooth or 

 nearly so. Sheaths smooth, the lower short and over- 

 lapping, the upper ones much longer; ligule about 2" 

 in length; blades 6'-i° long, i"-2" wide, scabrous; 

 panicle 7-1 ° in length or more, diffuse, the capillary 

 branches 4'-8' long, at length widely spreading; spike- 

 lets on long hair-like pedicels which are clavate- 

 thickened at the apex; outer scales unequal, acute or 

 short-awned, slightly scabrous; third scale, exclusive 

 of the awn, 2" long, about twice as long as the first 

 one, scabrous, the awn z"-g" in length. 



In dry sandy or rocky soil, Massachusetts to Kansas, 

 Florida and Texas. Bahamas and Cuba. Panicle usually 

 light purple. Sept.-Oct. 



Muhlenbergia glabriflorus Scribn., an imperfectly known species, is reported from Illinois. It 

 is said to resemble M. mexicana, and to differ from that species in the glabrous softer scales. 



35. BRACHYELYTRUM Beauv. Agrost. 39. 1812. 



A tall grass with flat leaves and a narrow panicle. Spikelets i-flowered, narrow, the 

 rachilla produced beyond the. flower and sometimes bearing a minute scale at the summit. 

 Scales 3; the outer small and inconspicuous, the lower often wanting; the third much longer, 

 rigid, s-nerved, acuminate into a long awn; palet scarcely shorter, rigid, sulcate on the back, 

 2-nerved. Stamens 2. Styles short, distinct. Stigmas plumose, elongated. Grain oblong, 

 free, enclosed in the scale and palet. [Greek, in allusion to the minute outer scales."] 



A monotypic genus of eastern North America. 



