MANUAL OF THE GRASSES OF THE UNITED STATES 



585 



130. LEPTOLOMA Chase 



Spikelets on slender pedicels; first glume minute or obsolete; second glume 

 3- to 5-nerved, nearly as long as the 5- to 7-nerved sterile lemma, a more or 

 less prominent stripe of appressed silky hairs down the internerves and margins 

 of each, the sterile lemma empty or enclosing a minute nerveless rudimentary 

 palea; fertile lemma cartilaginous, elliptic, acute, brown, the delicate hyaline 

 margins enclosing the palea. Branching perennials with brittle culms, felty- 

 pubescent at base, flat blades, and open or diffuse panicles, these breaking 

 away at maturity, becoming tumbleweeds. Type species, Leptoloma cognatum. 

 Name from Greek leptos, thin, and loma, border, alluding to the thin margins 

 of the lemma. 



Spikelets 2.5 to 3 mm. long; culms spreading from a knotty, often densely hairy, base. 



1. L. COGNATUM. 

 Spikelets 4 mm. long; plants branching at base, producing long slender rhizomes. 



2. L. ARENICOLA. 



1. Leptoloma cognatum (Schult.) 

 Chase. Fall witchgrass. (Fig. 844.) 

 Ascending from a decumbent knotty 

 often densely hairy base, often form- 

 ing large bunches, pale green, leafy; 

 culms 30 to 70 cm. long; blades 

 mostly less than 10 cm. long, 2 to 6 

 mm. wide, rather rigid; panicle one- 

 third to half the entire height of the 

 plant, purplish and short-exserted at 

 maturity, very diffuse, the capillary 

 branches soon widely spreading, pilose 

 in the axils, the spikelets solitary on 

 long capillary pedicels, narrowly 

 elliptic, 2.5 to 3 mm. long, abruptly 

 acuminate. % {Panicum cognatum 

 Schult., Panicum autumnale Bosc.) — 

 Dry soil and sandy fields, New Hamp- 

 shire to Minnesota, south to Florida, 

 Texas, and Arizona; northern Mexico. 

 A fairly palatable grass. 



2. Leptoloma arenfcola Swallen. 

 (Fig. 844A.) Culms 30 to 40 cm. long, 

 branching at base, with slender rhi- 

 zomes as much as 50 cm. long, some- 

 times branching, the scales thin, 

 softly pubescent; lower sheaths and 

 blades softly pubescent, the upper 

 glabrous; blades flat, 4 to 13 cm. long, 

 2 to 4 mm. wide; panicle nearly half 

 the entire height of the plant, at ma- 

 turity wider than long, few-flowered, 

 the branches stiffly spreading, scab- 

 rous, bearing 2 to 5 spikelets near the 

 ends and a few long stiff capillary 1- 

 flowered branchlets, the lower bearing 

 in addition 1 to few sterile branch- 

 lets; spikelets narrowly elliptic, acu- 



minate, 4 mm. long, with 5 to 7 pale 

 nerves, the internerves densely silky 

 with appressed dark-purple hairs; 

 fertile lemma 3.4 mm. long, dark 

 brown with pale hyaline margins. 

 % — Sand hills, Kennedy County, 

 Tex. 



131. STENOTAPHRUM Trin. 



Spikelets embedded in one side of 

 an enlarged and flattened corky rachis 

 tardily disarticulating toward the tip 

 at maturity, the spikelets remaining 

 attached to the joints; first glume 

 small; second glume and sterile lemma 

 about equal, the latter with a palea or 

 staminate flower; fertile lemma char- 

 taceous. Creeping stoloniferous peren- 

 nials, with short flowering culms, 

 rather broad and short obtuse blades, 

 and terminal and axillary racemes. 

 Type species, Stenotaphrum glabrum 

 Trin. Name from Greek, stenos, nar- 

 row, and taphros, trench, referring to 

 the cavities in the rachis. 



1. Stenotaphrum secundatum 

 (Wait.) Kuntze. St. Augustine 

 grass. (Fig. 845.) Culms branching, 

 compressed, the flowering shoots 10 

 to 30 cm. tall; blades mostly less than 

 15 cm. long, longer on the innova- 

 tions, in rich soil 4 to 10 mm. wide; 

 racemes 5 to 10 cm. long; spikelets 

 solitary or in pairs, rarely threes, 4 to 

 5 mm. long. % — Moist, especially 

 mucky soil, mostly near the seashore, 



