74 CONTRIBUTIONS FROM THE NATIONAL HERBARIUM. 



5. Paspalum longepedunculatum. LeConte. 



Open wooded elopes; Somerset and Fourmile Run, probably elsewhere. Sept. 

 Southern states, north to Md. 



6. Paspalum setaceum Michx. 



Gravelly or sandy clay soil; Takoma Park and Fourmile Run, probably elsewhere. 

 July-Sept. Southern states, north to N. J. 



7. Paspalum psammophilum Nash. 



Open sterile ground; found at Brookland in 1894. July. Atlantic Coastal Plain. 



8. Paspalum pubescens Muhl. 



Common in open woods and old fields. Aug.-Sept. Atlantic Coast to the Middle 

 West. 



9. Paspalum muMenbergii Nash. 



Found in the same habitat and range as the preceding species, rather commoner 

 in our region . 

 Doubtfully distinct, even vnrietally. 



9. PANICUM L. 



Plants annual. Panicles open. 

 Spikelets warty. Plants glabrous 13. P. verrucosum. 



Spikelets smooth. 

 Sheaths glabrous; first glume only one-fourth as long as the spikelet, truncate. 



1. P. dichotomiflorum. 

 Sheaths hirsute; first gliime as much as half the length of the spikelet, pointed. 

 (Capillaria.) 



Panicles drooping; spikelets 4.5-5 mm. long 6. P. miliaceum. 



Panicles erect; spikelets not over 3.5 mm. long. 

 Spikelets 3-3.5 mm. long, acimiinate; panicles narrow, usually less than half 



as broad as long, or sometimes spreading at maturity 2. P. flexile. 



Spikelets about 2 mm. long, acutish but not acuminate; panicles as broad as 

 long. 

 Panicles more than half the length of the entire plant; culms rather stout, 



erect or ascending 5. P. capillare. 



Panicles not more than one-third the length of the entire plant; culms 

 erect or decumbent-spreading. 

 Culms stout, soon decumbent-spreading; blades about 1 cm. wide. 



3. P. gattingeri. 

 Culms slender, erect, zigzag below; blades not over 6 mm. wide. 



4. P. philadelpMcum. 

 Plants perennial. 

 Spikelets short-pediceled, on short branchlets along the main branches of the 

 panicle, pointed. Sheaths keeled. (Agrostoidea.) 



Rootstocks present; culms but little compressed 12. P. anceps. 



Rootstocks wanting; culms strongly compressed, with keeled sheaths. 

 Ligule ciliate, 2-3 mm. long; panicle much exceeding the upper leaves. 



11. P. longlfolium. 

 Ligule erose or lacerate but not ciliate; panicle not much longer than the upper 

 leaves. 

 Fruit stipitate; spikelets conspicuously secund; panicle usually purple. 



10. P. stipitatum. 

 Fruit not stipitate; spikelets not conspicuously secund; panicle green or 

 slightly tinged with purple. 

 Spikelets 1.8-2 mm. long; panicle branches ascending or spreading. 



8. P. agrostoides. 

 Spikelets about 2.5 mm. long; panicle bninche.? erect or nearly so. 



9. P. condensum. 



