MANUAL OF THE GRASSES OF THE UNITED STATES 



3.5 to 4.2 mm. long. % —Moist 

 places in canyons and valleys, western 

 Texas to Arizona; Mexico. 



Panicum bulbosum var. minus 

 Vasey. Culms slender, mostly less 

 than 1 m. tall, the corms smaller 

 than in the species; blades mostly 

 2 to 4 mm. wide; spikelets 2.8 to 3.2 

 mm. long. % (P. bulbosum var. 

 sciaphilum Hitchc. and Chase.) — 

 Same range as the species and more 

 common in the United States. 



9. Virgata. — Perennials from stout 

 rhizomes; culms mostly stout; 

 ligules membranaceous, ciliate; 

 blades linear, mostly firm; spike- 

 lets turgid, usually gaping, strong- 

 ly 5- to 9-nerved, glabrous, 

 pointed; lower floret usually 

 staminate; fruit smooth and 

 shining. 



149. Panicum repens L. (Fig. 

 1058.) Culms rigid, 30 to 80 cm. 

 tall, erect from the nodes of strong 

 horizontal often extensively creeping 

 rhizomes, clothed at base with blade- 

 less sheaths; sheaths more or less 

 pilose; blades flat or folded, 2 to 5 

 mm. wide, sparsely pilose to gla- 

 brous; panicle open, 7 to 12 cm. long, 

 the somewhat distant branches stiffly 

 ascending; spikelets 2.2 to 2.5 mm. 

 long, ovate; first glume about one- 

 fifth as long as the spikelet, loose, 

 truncate. % — Sea beaches along 

 the Gulf coast, Florida to Texas. 

 Tropical and subtropical coasts of 

 both hemispheres, possibly introduced 

 in America. 



150. Panicum gouini Fourn. (Fig. 

 1059.) Resembling P. repens, but the 

 culms usually less than 30 cm. tall; 

 sheaths and blades usually glabrous; 

 panicle smaller, more densely flow- 

 ered; first glume longer. % — Sea 

 beaches, Alabama to Louisiana; Gulf 

 coast of Mexico. 



151. Panicum virgatum L. Switch- 

 grass. (Fig. 1060.) Plants usually in 

 large bunches, green or glaucous, with 

 numerous scaly creeping rhizomes; 

 culms erect, tough and hard, 1 to 2 

 m., rarely to 3 m., tall; sheaths gla- 



697 



Figubb 1059. — Panicum gouini. Two views of spike- 

 let, and floret, X 10. (Type.) 



brous; blades 10 to 60 cm. long, 3 

 to 15 mm. wide, flat, glabrous, or 

 sometimes pilose above near the 

 base, rarely pilose all over; panicle 

 15 to 50 cm. long, open, sometimes 

 diffuse; spikelets 3.5 to 5 mm. long, 

 acuminate; first glume clasping, two- 

 thirds to three-fourths as long as the 

 spikelet, acuminate or cuspidate; 

 fruit narrowly ovate, the margins of 

 the lemma inrolled only at base. % 

 — Prairies and open ground, open 

 woods, and brackish marshes, Nova 

 Scotia and Ontario, Maine to North 

 Dakota and Wyoming, south to 

 Florida, Nevada, and Arizona; Mex- 

 ico and Central America. 



Panicum virgatum var. cubense 

 Griseb. Culms more slender, usually 

 solitary or few in a tuft; panicle 

 narrower, with ascending branches; 

 spikelets 2.8 to 3.2 mm. long, the 

 second glume and sterile lemma not 

 extending much beyond the fruit. % 

 — Pine woods, Coastal Plain, Massa- 

 chusetts to Florida, Michigan, Wis- 

 consin, Tennessee (Coffee County), 

 and Mississippi; Michigan; Cuba. 



Panicum virgatum var. spissum 

 Linder. Culms from short stout 

 knotty rhizomes. % — Nova Sco- 

 tia to Pennsylvania. 



152. Panicum havardii Vasey. (Fig. 

 1061.) Pale green, glaucous, glabrous 

 throughout; culms robust, solitary, 

 1 m. tall or more, erect from creeping 

 rhizomes; blades 5 to 10 mm. wide, 

 tapering into long involute-setaceous" 

 tips; panicle as much as 40 cm. long; 

 spikelets 6 to 8 mm. long. % — 

 Arroyos and sand hills, western 

 Texas and southern New Mexico; 

 northern Mexico. 



