18 POACEAE. 



28. LEPTOCHLOA Beauv. Often tall grasses, witli flat or convolute 

 leaf-blades, and an inflorescence consisting of very many long slender spikes 

 arranged in a panicle, rarely approximate at the summit of the stem. Spikelets 

 small, close, or rarely scattered, 2-several-flowered, rarely 1-flowered, flattened, 

 sessile, alternate in 2 rows. Scales 3-several, keeled, obtuse, acute, or shortly 

 awned, the 2 lower empty, a little unequal, usually shorter than the spikelet, 

 or in the 1-flowered spikelets exceeding the liiird scale, the remaining scales 

 more obtuse or sometimes bearing a slender awn, each of the lower enclosing 

 a prominently 2-keeled palet and a flower, the upper empty. Stamens 3. 

 Styles distinct. Stigmas plumose. 



i>^ 1. L. domingensis (Jacq.) Trin. Stems 2-10 dm. tall: leaf -blades 1-3 dm, 

 long, 1 cm. wide or less: inflorescence 1-2 dm. long: spikes 3-10 cm. long: 

 spikelets 2-3 mm. long: flowering scales 1.75-2.25 mm. long, acute, the lateral 

 nerves pilose for part way above the middle, the midnerve, hispidulous above 

 the middle. — Hammocks and cultivated grounds, U. keys, L. keys. — (Bah., 

 Cuba, Ant.) 



29. PHRAGMITES Trin. Tall erect plants with flat usually broad leaf- 

 blades and ample terminal panicles. Spikelets 2-several-flowered, the lower 

 flower staminate, the remainder perfect. Scales 4-several, the first much shorter 

 than the second, the remaining scales long-acuminate. 



d^l. P. Phragmites (L.) Karst. Stems 1-5 m. tall, from long rootstocks: leaf- 

 blades 1.5-3 dm. long or more, 1-5 cm. wide, flat: panicle ample, 1.5-3 dm. 

 long or more: spikelets crowded, the flowering scales 10-12 mm. long. — Shore 

 hammocks and lime-sinks, U. keys. — [E. K.] — {Bah.) — Common-reed. 



30. MONANTHOCHIiOE Engelm. Perennial creeping or stoloniferous 

 monoecious grasses, with short rigid convolute leaf-blades crowded at the 

 nodes, and an inconspicuous inflorescence concealed among the leaves. Spike- 

 lets unisexual, the staminate hardly sessile and in pairs, or stipitate and single. 

 Scales 4 or 5, the 2 outer somewhat resembling the floral leaves, membranous 

 and sheathing at the base, linear, rigid and spreading above, many-nerved, the 

 remaining scales membranous, firmly hyaline. 



']0 1. M. littoralis Engelm. Branches densely tufted from creeping stems, 1-5 

 dm. tall, stiff, wiry: leaf -blades crowded on short branches, widely spreading, 

 1.5 cm. long or less, stiff, often curved. — Hammocks, sand-dunes and shores, 

 U. keys, L. keys, L. S. keys. — (Cuba.) 



31. TRIDENS E. & S. Usually perennial grasses, with the inflorescence 

 of open or contracted panicles. Spikelets 3-many-flowered. Scales 5-many: 

 flowering scales 3-nerved, the midnerve or all the nerves excurrent, the mid- 

 nerve and the lateral nerves or the margins pilose. 



""1. T. eragrostoides (Vasey & Scribn.) Nash. Stems 3-12 dm. tall: leaf -blades 

 2-3 dm. long, 4-7 mm. wide: panicle 1.5-3 dm. long, its rough branches ascend- 

 ing, 3-12 cm. long: spikelets 7-10-flowered, 2.5 mm. broad, ovate: flowering, 

 scales about 2.5 mm. long, oval and about 1.5 mm. wide when spread out, the 

 apex rounded or nearly truncate, denticulate, the midnerve usually excurrent. 

 — -Hammocks and lime-sinks, Key West. 



"■ ' 32. DIPLACHNE Beauv. Tufted often tall grasses, with an inflorescence 

 of numerous long slender spikes or racemes (rarely reduced to one and 

 terminal), racemosely arranged on a long axis. Spikelets linear, sessile or 

 nearly so, many-flowered. Scales many, membranous. 



