GRAMINEAE 33 



1. D. spicata (L.) Greene. Spike-Grass. Flowering culms 5' high, 

 the sterile much taller, rigid and very leafy : spikelets clustered, 7-12, 

 ovate-lanceolate, 8'^ long, 2A^' wide, 8-12-flowered. — A large patch of 

 the pistillate plants adventized in the railroad yards at Sheffield. Our 

 form is var. siricta Scribn. May-June. 



46. DACTYLIS L. 



Spikelets 3-5-flowered in one-sided clusters in a dense panicle. Two 

 lower glumes empty, scarious-margined, mucronate-pointed, unequal, the 

 flowering 5-nerved, larger and short-awned or mucronate. Palet shorter, 

 2-keeled. 



1. D. glomerata L. Orchard Grass. A rough perennial 2°-4° 

 high : panicles 5^-8^ 'ong, its branches naked at base : spikelets 4^^ long, 

 in dense clusters, 3-5 flowered. — Often planted and frequently found in 

 waste places, yards and meadows throughout. May-June. 



47. POA L. Meadow Grass. 

 Spikelets compressed, 2-10-flowered, paniculate. Glumes keeled, the 

 two empty ones shorter than the flowers, 1-3-nerved. Flowering glumes 

 scarious margined, 5nerved, usually with a tuft of cobwebby hairs at 

 base, and the chief nerves pubescent. Palet shorter, 2-nerved. 



Annuals less than 12^ high. 



Flowering glumes cobwebby at base. 1. P. Chapmaniana. 



Flowering glumes not cobwebby at base. 2. P. annua. 



Perennials, more than 12^ high. 



Culms flattened. 3. P. compressa. 



Culms terete, panicle branches erect. 4. P. nemoralis. 



Culms terete, panicle branches spreading. 

 Panicle branches 2-6 together. 

 Spikelets shorter than pedicels. 



Flowering glumes obscurely nerved. 5. P. flava. 



Flowering glumes strongly nerved. 



Flowering glumes silky-pubescent. 6. P. pratensis. 



Flowering glumes not silky-pubescent. 7. P. trivialis. 

 Spikelets exceeding pedicels. 8. P. fiylvesiris. 



Panicle branches 1-2 together. 9. P. IVolfii. 



1. P. Chapmaniana Scribn. Southern Spear-grass. Tufted, 3M 2^ 

 high, erect: panicle 1^-4^ long : spikelets 1Y'' long, 3-7-flowered : flow- 

 ering glume 1^^'' long, cobwebby at base, rather obscurely 3-5-nerved, 

 the nerves pilose. — Common in sandy soil. April-May. 



2. P. annua L. Spear-grass. Like the last but ascending or spread- 

 ing : flowering glumes distinctly 5-nerved and not cobwebby at base. — 

 Sparingly adventized at Courtney. Maj'-July. 



3. P. compressa L. Wire Grass. Culms 12^-20' high, flattened, 

 from long spreading rootstocks : panicle IV-S^ long, 3^'-6^^ wide: branches 

 ascending, spikelet-bearing throughout : spikelets H'^long, 3-10-flowered: 

 flowering glume 3-nerved, sparingly pubescent on the nerves toward the 

 base. — In waste places. Well distributed but uot common. June-August. 



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