78 POACEAE 



54. Paspalum distlchum L. Stems 1-6 dm. tall, from a long stout rootstock : 

 leaf-sheaths compressed, keeled, usually crowded and overlapping, especially at the base 

 and on the innovations, glabrous, or more or less hairy on the margins ; blades com- 

 monly less than 1 dm. long, 3-6 mm. Avide, generally glabrous : racemes terminal, in pairs, 

 ascending, 2-5 cm. long : spikelets singly disposed, ovate, 2.5-3 mm. long, acute, tlie 

 2 outer scales firm, o-nerved, rarely 7-nerved, the first scale glabrous, the second appressed- 

 pubescent, the third apiculate, strongly pubescent at the apex. 



In sandy soil, on the seashore or along rivers, Virginia to Missouri, Florida and Texas, and on the 

 Pacific coast. Also in tropical America. Summer and fall. 



55. Paspalum vaginatvun Sw. Stems 2-6 dm. tall, from a long stout rootstock : 

 leaf-sheaths compressed, keeled, usually crowded and overlapping, at least at the base and 

 on the innovations, glabrous; blades folded, or involute when dry, 1.5 dm. long or less, 

 2-4 mm. wide, glabrous, or sparingly hairy above at the very base : racemes terminal, usu- 

 ally in pairs, rarely more or but a single one, erect or ascending, 3-7 cm. long : spikelets 

 singly disposed, ovate-lanceolate, acute, 3-4 mm. long, the 2 outer scales glabrous, thin, 

 the first scale 4-nerved, the lateral nerves approximate at the margin, the midnerve sup- 

 pressed, the second scale 5-nerved, the lateral nerves rather near together, the third scale 

 glabrous at the apex or with 2 or 3 hairs. 



Along the seashore, Florida to Texas. Also in the West Indies. Summer and fall. 



21. DIMORPHOSTACHYS Fourn. 



Perennial grasses with simple or somewhat branched stems, flat leaf -blades and one-sided 



racemes. Spikelets borne in pairs, the one short-, the other longer-pedicelled, the former 



with the first scale turned to one side and often much longer than the corresponding scale 



in the other spikelet. Scales 4, tlie outer 3 membranous ; fourtli scale indurated in fruit, 



with its opening turned away from the rachis, and enclosing a palet of similar texture and 



a perfect flower. Stamens 3. Styles long, distinct. Stigmas plumose. 



Spikelets 2.3-2.5 mm. long : leaf-blades usually short, with naked margins. 1. D. Lh-ummondii. 



Spikelets 2.8-3 mm. long : leaf-blades with ciliate margins. 2. D. ciliifera. 



1. Dimorphostachys Dnimmondii Fourn. Stems tufted, 3-7 dm. tall, rather slen- 

 der, glabrous : leaf-sheaths glabrous excepting the ciliate margins ; blades erect, gla- 

 brous, or sometimes with a few scattered hairs on the surface, generally 1.5 dm. long or 

 less, occasionally longer, 1-1.5 cm. broad : racemes 2-4, 4-9 cm. long : spikelets in pairs, 

 2.3-2.5 mm. long and about 1.5 mm. broad, obovate or elliptic ; scales 4 (rarely 3), the 

 first and second scales rather strongly pubescent, the first scale very small, nerveless, the 

 second and third scales 5-nerved, the latter glabrous. \^Paspalum Drummondii ( Fourn. ) 

 Vasey. ] 



In low grounds, Texas and Mexico. Summer and fall. 



2. Dimorphostachys ciliifera Nash. Stems tufted, glabrous, or sometimes papillose- 

 hirsute toward the base, 7-11 dm. tall : leaf-sheaths ciliate, otherwise glabrous, or the 

 lower ones papillose-hirsute ; blades erect or nearly so, the larger ones 2-3 dm. long and 

 1-1.5 cm. wide, ciliate on the margins, sparingly pubescent on the surface with scattered 

 hairs: racemes 2 or 3, finally spreading, 7-9 cm. long: spikelets crowded in pairs, 2.8-3 

 mm. long and about 1.8 mm. broad ; scales 4, the glabrous first scale very small or occa- 

 sionally i as long as the spikelet and acuminate, nervele.ss, or in the latter case l-nerved, 

 the second and third scales 5-nerved, the former glabrous, the latter sparingly pubescent 

 with short appressed hairs. 



In moist soil, southern peninsular Florida. Fall. 



22. ANASTROPHUS Schlecht. 



Perennial grasses, with compressed stems and siieaths, the stems creeping at the base, 



the inflorescence consisting of 2-several (rarely 1) unilateral more or less spreading spikes. 



Spikelets articulated below the empty scales, 1 -flowered, singly and alternately disposed in 



2 rows on one side of a narrow rachis, appressed, narrow, sessile, acute or acuminate. 



Scales 3, the 2 outer empty, membranous, the third one firmer, glabrous and shining, at 



length indurated, with its back turned away from the rachis, enfolding a shorter palet of 



similar texture and a perfect flower. Stamens 3. Styles distinct. Stigmas plumose. 



Spikelets 4-6 mm. long. 1. A. paspaloides. 

 Spikelets 2-2.5 mm. long : 



Ovate: lower leaf-blades 8-12 mm. wide. 2. A. platycaulis. 



Elliptic : lower leaf-blades rarely exceeding 6 mm. in width. 3. ^1. compressus. 



1. Anastrophus paspaloides (Michx. ) Nash. Perennial, with creeping stolons. 

 Stems flattened, 2-8 dm. tall : leaf-sheaths compressed and, like the blades, pubescent or 



