32 GRAMINEAE 



44. DACTYLOCTBNIUM Willd. 

 1. Daotylootemum Aegyptium (L.) Willd. Egyptian Grass. 

 (Man. p. 124; I. F./. 416.) In waste places and cult, ground, southern 

 N. Y. and Va. to 111. and Cal., Fla. and Mex. Pennsylvania; Dei,a- 

 ware; Phii,adei,phia. 



45. PHRAGMITBS Trin. 

 1. Phragmites Phragmites (L.) Karst. Reed. (Man. p. 126; I. F. 

 / 420.) In swamps nearly throughout the U. S., extending north to N. 

 S., Man. and B. C. Also in Europe and Asia. — Pennsylvania : Dela- 

 ware ; Chester ; Erie, Presque Isle ; Philadelphia, Point Breeze. 



46. TRIDENS R. & S. 



1. Tridens seslerioldes (Michx.) Nash. Tall Red-top. (Man. p. 

 126 ; I. F./. 42/. ) In fields, N. Y. to Kans., Fla. and Tex. — Pennsylvania : 

 DELAWARE; Chester; Bucks; Luzerne; Northampton; Lan- 

 caster ; Huntingdon ; Philadelphia ; York ; Franklin. 



47. TRIPLASIS Beauv. 



1. Trlplasis purpurea (Walt.) Chapm. Sand-grass. (Man. p. 127 ; 

 I. F. y. 424. ) In sand, especially on sea beaches, Me. to Tex. and along 

 the Great Lakes. Also from Neb. to N. Mex. — Pennsylvania : Erie, 

 Presque Isle. 



48. ERAGROSTIS Beauv. 



Stems not creeping- : flowers perfect. 

 Annuals. 

 Spikelets z-5-flowered. 

 Pedicels and branches of the panicle short : stems usually branched 



above. 1. £. Frankii. 



Pedicels and branches of the diffuse panicle long and capillary : stems 

 branched only at the base. 2. £. capillaris. 



Spikelets more than 5-flowered. 

 Spikelets 1.5 mm. wide or less : palets remaining attached to the contin- 

 uous rachis for some time after the flowering scales have fallen. 

 Flowering scales thin, usually bright purplish, the lateral nerves faint 



or wanting : spikelets about i mm. wide. 3. E. ptlosa. 



Flowering scales flrm, usually dull purple or green, the lateral nerves 

 very prominent : spikelets about 1.5 mm. wide. 4. E. Purshii. 

 Spikelets exceeding •j mm. wide : palets falling with the flowering 

 scales and the intemodes of the rachis. 

 Spikelets 2 mm. wide : lower flowering scales about 1.5 mm. long. 



5. E. Eragrostis. 

 Spikelets 2.5-3 ™™- wide : lower flowering scales 2-2.5 nim. long. 



6. E. major. 

 Perennials. 7. E. pectinacea. 



Stems creeping, rooting at the nodes. 8. E. hypnoides. 



1. EragTostlB Frankii Steud. Frank's Eragrostis. (Man. p. 130; 

 I. F./. 4zg.) In moist places, N. Y. to Minn., Miss, and TS.a.ns.— Penn- 

 sylvania : Chester ; Lancaster ; Monroe ; Northampton. 



