16 POACEAE. 



branous, acute or obtuse, the first shorter than the second. Stamens 2 or 3. 

 RUSH-GRASS. 



Plants without long rootstocks : splkelets 2 mm. long or less. 

 Panicle short, the branches usually spreading. 



Blades" of the larger leaves 5 cm. long or less. 1. 8. argutua. 



Blades of the larger leaves 1 dm. long or more. 2. S. dominyensis. 



Panicle elongate, the branches erect and appressed. 3. 8. anguatus. 



Plants with long rootstocks : spikelets 2-2.5 mm. long. 4. S. virginicus. 



1. S. argutus (Nees) Kunth. Stems 3 dm. tall or less: leaf -blades 2-4 mm. 

 wide, acuminate: panicle 4-8 cm. long, its branches at first appressed, finally 

 widely spreading: spikelets 1.5-1.8 mm. long. Hammocks, U. keys, L. keys. 

 (Bah., Cuba, Ant.) 



2. S. domingensis (Trin.) Kunth. Stems 3-5 dm. tall, erect: leaf-blades 3-5 

 mm. wide, long-acuminate: panicle 8-15 cm. long, its branches at first erect, 

 finally spreading: spikelets about 2 mm. long. Hammocks and sand-dunes, 

 U. keys, L. keys. (Bah., Cuba, Ant.) 



3. S. angustus Buckl. Stems 3-12 dm. tall: leaf -blades 2-6 mm. wide, atten- 

 uate into a long slender point, the basal ones 2-3 dm. long: panicle 1-4 dm. 

 long: spikelets 1.5-2 mm. long, crowded on the short panicle-branches: second 

 scale oblong to ovate, about the length of the spikelet. Hammocks, L. keys. 

 [E. K.] (Ber., Bah., Cuba, Ant.) 



4. S. virginicus (L.) Kunth. Stems 1.5-6 dm. tall: leaf -blades 2.5-20 cm. 

 long, 4 mm. wide or less at the base, distichous, involute on the margins and at 

 the summit: panicle 2.5-8 cm. long, 4-10 mm. wide: spikelets 2-2.5 mm. long. 

 Hammocks and sand-dunes, U. keys, L. keys. [E. K.] (Ber., Bah., Cuba, 

 Ant.) 



21. AVENA L. Annual or perennial herbs, varying in habit. Spikelets 

 generally large, usually 2-several-flowered, rarely 1-flowered, the rachilla 

 articulate between the fertile flowers, the lower flowers perfect, the upper ones 

 staminate or wanting. Scales 4-several, rarely 3, the 2 outer membranous, 

 persistent; the flowering scales 5-9-nerved, rounded on the back, the scales 

 enclosing perfect flowers bearing a dorsal twisted geniculate awn, the upper 

 empty ones or those infolding staminate flowers awnless. 



1. A. sativa L. Annual: stems 8-15 dm. tall: leaf -blades 2.5 dm. long or less, 

 5-10 mm. wide or more: panicle usually 1.5-4 dm. long: empty scales 2-3 cm. 

 long, acuminate, the flowering ones shorter, awned or awnless. Cultivated 

 grounds and waste places, U. keys. Nat. of the Old World. OAT. 



22. SPARTTNA Schreb. Erect or decumbent plants with the spike-rachis 

 extending beyond the spikelets. Spikelets sessile or nearly so, much crowded and 

 imbricate. Scales 3, firm-membranous, the 2 outer keeled, the flowering scale 

 equalling or a little longer and broader than the second scale. MARSH-GRASS. 

 1. S. junciformis Engelm. & Gray. Stems rigid, often slender, 3-10 dm. tall: 

 leaf -sheaths thick, hard, the lower ones shining; blades involute, 5 dm. long or 

 less: panicle 1-2 dm. long, narrow, strict: spikelets about 7 mm. long. Ham- 

 mock and sand-dunes, U. keys, L. keys. [E. K.] 



23. CAPBIOLA Adans. Stoloniferous plants, the stems as well as the 

 stolons often creeping. Spikelets small. Scales 3, the 2 outer persistent, thin, 

 keeled, the flowering scale membranous, broader, its keel ciliate. 



1. C. Dactylon (L.) Kuntze. Stems 1-3 dm. tall, from long creeping and 

 branching rootstoeks: leaf -blades 2.5-5 cm. long, 2-4 mm. wide: spikes 1-5 cm. 



