144 POACEAE 



white hairs, the apex acuminate, entire or slightly 2-toothed, the awn terminal or ari^in^r 

 between the minute teeth. Stamens 3. Styles short, distinct. 



1. Erioneuron pilosum (Buckl. ) Nash. Stems densely tufted, 0.4-3 dm. tall, naked 

 above : leaf-sheaths sparingly pilose at the summit ; blades erect, folded, linear, obtuse or 

 abruptly acutish at the apex, thick, with broad wliite serrulate margins, papillose-hirsute, 

 especially beneath, the basal numerous, 2-8 cm. long, tliose on the stem usually 3 cm. 

 long or less : panicle racemose or nearly so, 1-3 cm. long : spikelets 3-8, crowded, 1-1.5 

 cm. long, about 5 mm. broad, the empty scales acuminate, 1-nerved, the flowering scales, 

 exclusive of the awn, 5.5-6 mm. long, acuminate, entire or slightly toothed at the apex, 

 the internerves pilose at the base, the nerves pilose on the lower i and the midnerve 

 also above the middle, the longer hairs about 2 mm. long, the awn 1-1.5 mm. long. 



In dry gravelly soil, Kansas and Colorado to Texas and Arizona. Summer. 



99. TRIPLASIS Ikauv. 

 Perennial grasses, with very narrow flat or convolute leaf-blades and terminal con- 

 tracted or open somewhat branched panicles. Spikelets shortly pedicellate, 2-6-flowered, 

 the flowers perfect or the upper staminate, the glabrous rachilla articulated between the 

 flowers, the internodes long. Scales 4-8, membranous, the 2 lower empty, keeled, acute 

 shorter than the rest, the flowering scales distant on the rachilla, dorsally rounded at the 

 base, 3-nerved, the lateral nerves pilose, deejjly 2-lobed at the apex, the lobes obtuse, acute 

 or acuminate, each with a glabrous or pubescent awn arising between the lobes, the callus 

 long and subulate ; palet shorter than the scale, compressed, 2-keeled, the keels long-ciliate. 

 Stamens 3. Styles short, distinct. Stigmas plumose. 



Flowering scale ]-^ as broad as long or more, with a shorter straight awn 3 mm. long 

 or less. 

 Lobes of the flowering scale rounded or truncate at the irregularly and minutely 



toothed apex ; awn less than 2 mm. long. 1. T. purpurea. 



Lobes of the flowering scale acute or acutish at the apex ; awn 2.5-3 mm. long. 2. T. intermedia. 



Flowering scale 1/5 as broad as long, its lobes acuminate, pointed, the awn longer 



than the scale, 6 mm. in length or more, recurved, at least when dry. 3. 1. Americana, 



1. Triplasis purpurea (Walt.) Chapm. Stems tufted, 2-8 dm. tall: leaf-sheaths 



rough ; blades 15 cm. long or less, 1-3 mm. wide, rough : panicle finally exserted, its 



branches in I's or 2's, 4 cm. long or less : spikelets on short hispidulous pedicels : scales 



4 or 5 ; the 2 outer empty, acuminate ; flowering scales abotit 4 mm. long, 1.75 mm. wide 



when spread out, divided about \ way down, the lobes rounded or ti'uncate at the irregularly 



and minutely toothed apex, the awn equalling or a little exceeding the lobes, pilose on the 



lower half, less than 2 mm. long, straight. [ T. sparsiflora Chapm.] 



In sandy soil, usually along the coast, Ontario to Florida and Texas. Also along the Great Lakes 

 and from Missouri and Nebraska southward. Summer. Sand (tRass. 



2. Triplasis iuterm^dia Nash. Stems densely tufted, 4-8 dm. tall, slender: Icaf- 

 sheaths very rough, papillose-hirsute toward the base with long ascending hairs ; blades 

 13 cm. long or less, involute when dry, rough, hirsute above : panicle finally exserted, its 

 branches in rs-3's, pubescent at the base, rough, the larger ones 2-4 cm. long : spikelets on 

 short pubescent pedicels, 8-10 mm. long; scales 5 or 6; the 2 outer empty, acuminate; 

 flowering scales 4.5 mm. long and 1.5 mm. wide when spread out, divided from J-.] their 

 length, the lobes acute to somewhat obtuse, the awn 2.5-3 ram. long, straight, nuich exceed- 

 ing the scale. 



In dry sandy soil, southern peninsular Florida. Summer. 



3. Triplasis Americana Keauv. Stems tufted, 3-8 dm. tall, slender, puberulent : 

 leaf-sheaths smooth ; blades 15 cm. long or less, less than 2 mm. wide, smooth, the upper 

 surface minutely pubescent : panicle finally exserted, its branches single or in pairs, 3 cm. 

 long or less : spikelets on short hispidulous pedicels ; scales 4 or 5 ; the 2 outer empty, 

 acuminate ; flowering scales about 5 mm. long and 1 mm. broad when spread out, divided to 

 the middle, the lobes sul)ulate, acuminate, pointed, the awn nuich exceeding the scale, usu- 

 ally reflexed, at least when dry, pilose for about | its length, 6-8 mm. long. 



In dry sandy soil along the coast, North Carolina to Florida and Texas. Summer. 



100. REDFIELDIA Vasey. 

 Tall perennial grasses, with long narroAV leaf-blades and a terminal ample diffuse pan- 

 icle, its branches long and capillary. Spikelets numerous, 1-3-flowered, the flowers perfect. 

 Scales 3-5, acute, the 2 outer empty, about cfjual in length, the remaining scales com- 

 pressed-keeled, larger, each ftu-nished with a basal ring of hairs, 3-nerved, the middle 



