

No. 24 



STIPA FLEXUOSA Vasey. 



Culms closely set on a short horizontal rootstock with slender roots, erect, Ljto 

 3 feet high, slender, terete, smooth, unbranched. 



Leaves of the stem 2 to 4; sheaths smooth, close, usually imbricated ; blades about 

 1 line broad, a few inches to 1 foot long, involute or the upper flat, glabrous on 

 the back, minutely pubescent on the upper surface, hairy at the angle of the 

 ligule; ligules membranaceous, 1 to 2 lines long, lacerate when old, broader than 

 the blade. 



Inflorescence paniculate. Panicle 6 to 12 inches long, erect; rachis slender, ter- 

 ete, glabrous; branches slender, flexuous, few-angled, scabrous, bearing towards 

 the apex a few pedicelled spikelets. 



Spikelets single, 1-flowered, on pedicels about 2 lines long, lanceolate, awl-shaped 

 when closed, 6 to 9 lines long exclusive of the awn. 



Glumes 3; first narrowly lanceolate, acute, membranaceous; glabrous, 1-nerved 

 or with 2 lateral nerves at the base, hyaline above, green or purple below, as 

 long as the spikelet; second similar, about one-fifth shorter, 3- to 5-nerved; third 

 (flowering) about 2i lines long closely involute about the flower into an awl-shaped 

 terete body, villous on the outside, coriaceous at maturity, 5-nerved apex produced 

 into a slender scabrous awn twisted in a right-handed spiral for about 5 lines, then 

 bent, then twisted as before for about 3^ lines, then bent, and above the second 

 bend not twisted. Rachilla elongated between the second and third glumes to the 

 length of | line, villous. 



Flower hermaphrodite. Palet about one-third the length of the glume, oblong, 

 obtuse, hyaline. Stamens 3; anthers linear, 1 to 1^- lines long, apex of each cell of 

 the anther bearing a small tuft of hairs. Stigmas rather short, oblong. 



Grain awl-shaped, about 2 lines long, inclosed in the glume, rachilla disarticu- 

 lating just above the second glume, detached portion ending in a sharp point. 



Plate XXIV; a, and b, spikelet, the parts spread open and the upper portions 

 of the rachilla detached at the point of disarticulation. The figure does not show 

 the regular bends in the awn, nor the tufts of hairs at the apex of the anther cells. 



This is more slender than S. avenacea, with smaller flowers, the flowering glume 

 pubescent throughout, and the apex crowned with a row of white hairs. 



