17. Paspalum Difforme Le Conte. Le Conte's Paspalum

Fig. 304

Paspalum difforme Le Conte, Journ. de Phys. 91: 284. 1820.

A perennial, usually glaucous, grass, with short flat leaf-blades, and large glabrous spikelets. Culms l 1/2°-3° tall; leaf-sheaths glabrous, or the outer basal ones sometimes pubescent, the uppermost one usually blade-less; blades erect or ascending, thickish, glabrous, or the upper surface with long hairs, linear to linear-lanceolate, acuminate, commonly less than 6' long and 5" wide; racemes usually 2, or sometimes 1 or 3, rarely 4, erect or ascending, less than 4' long, the rachis often flexuous and about 1/2" wide; spikelets singly disposed, sometimes in pairs, 1 1/2"-2" long and 1 1/4"-1 1/2" wide, oval, the outer 2 scales 3-nerved, the third scale brownish when mature.

In sandy soil, New Jersey and Maryland to Florida and Texas. Aug.-Sept.

18. Paspalum Floridanum Michx. Florida Paspalum

Fig. 305

Paspalum floridanum Michx. Fl. Bor. Am. 1: 44. 1803. Paspalus macrospermus Fluegge, Gram. Monog. 172. 1810. Paspalum arundinaceum Poir. in Lam. Encycl. Suppl. 4:

310. 1816. Paspalum floridanum glabratum Engelm.; Vasey, Contr.

U. S. Nat. Herb. 3: 20. 1892.

A tall perennial, sometimes glaucous, with long glabrous or hirsute leaves, and glabrous spikelets. Culms 3°-6 1/2° tall; leaf-sheaths rather loosely embracing the culm; blades erect or nearly so, flat, rather firm, linear, 1°-2 1/2° long, 3"-8" wide; racemes 3-6, rarely fewer, erect or neary so, 3'-6' long, the rachis about 3/4" wide; spikelets singly disposed or in pairs, 1 3/4"-2 1/4" long and 1 1/4"- 1 3/4|" wide, oval, the outer 2 scales 3-nerved.

In dry or moist soil, Delaware to Kansas, south to Florida and Texas. Sept.

19. Paspalum Dilatatum Poir. Tall Paspalum

Fig. 306

Paspalum dilatatum Poir. in Lam. Encycl. 5: 35. 1804. Paspalum ovatum Nees, Trin. Gram. Pan. 113. 1826.

Culms erect, 1 1/2°-6° tall, smooth and glabrous. Sheaths compressed, smooth and glabrous; leaves 1° or less long, 1 1/2-6" wide, long-acuminate, rather scabrous on the margins, sometimes with a tuft of hairs at the base; racemes 3-8, 2'-5' long, erect or ascending, the rachis less than 1" wide, somewhat flexuous, scabrous; spikelets in pairs, about 1 1/2" long, acute; outer scales 5-7-nerved, the first ciliate with long hairs on the margins, the second glabrous or sparsely ciliate, the third nearly orbicular, minutely punctate-striate.

In moist soil, Virginia and Tennessee to Florida and Texas. Aug.-Sept. Large Water-grass.

20. Paspalum Distichum L. Joint-Grass

Fig. 307

Paspalum distichum L. Syst. Nat. Ed. 10, 855. 1759. Digitaria paspaloides Michx. Fl. Bor. Am. 1: 46. 1803. Paspalum Micliauxianum Kunth, Rev. Gram. 25. 1829.

Culms erect, 4'-2° tall, extensively creeping at the base. Sheats smooth, sometimes ciliate on the margins, or sparsely pubescent; blades flat, 1 1/2'-5' long, l"-3" wide, acuminate, smooth; racemes I-2 1/2 long, in pairs, or occasionally with a third, the rachis flat, 1/2"-1" wide, smooth; spikelets 1 1/4"-1 1/2" long, ovate, acute, nearly sessile in 2 rows, the outer scales 5-nerved, the first glabrous, the second ap-pressed-pubescent, the acute third sparingly bearded at the apex.

On the seashore or along rivers, Virginia to Missouri, California and Washington, south to Florida, Texas and Mexico. Also in tropical America. Aug.-Sept. Knot-grass. Devil's-grass. Seaside-millet.