ELISHA MITCHELL SCIENTIFIC SOCIETY. 23 
Nodes not barbed, sheaths pubescent. 
Branches of panicle erect or ascending, leaves spread- 
RMSE IS al Sard ents ~ thins a0 au ty Spa AAO tae Shines phys he 13. P. malacon. 
Branches of panicle ascending, leaves erect 14. P. Ljie- 
bergii. 
Branches of panicle spreading ... 15. P. Scribnerianum. 
Ligule, nodes and sheaths glabrous. 
Spikelets elliptical, 14%’’ long, leaves 3’—S’ long 16. P. equi- 
laterale. 
Spikelets 14%’ long, leaves about 2° long. 
Leaves spreading, stem nearly naked below 17. P. Ashei. 
Leaves ascending, stem leafy below 18. P. Webberianum. 
Leaves erect, 2’’—3’’. wide, somewhat rounded at the base, pubescent, 
at least the lower ones, spikelets broadly elliptical, 14’’—1%” long. 
Stem erect, strict, leaves not crowded (western) 19. P. Wilcox- 
ianwum, 
Stems much branched from the base, diffuse (southern) 20. P. 
Georgianuin. 
Leaves 3’’—10’’ wide, lanceolate, erect or ascending, clasping by a 
cordate, ciliate base: lower sheaths overlapping, longer than the in- 
ternodes; spikelets small, %*’ long or less, nearly spherical, num- 
erous. 
BResves @'=-10 wide, ascenditg 20.) 64)... os. ss 21. P. polyanthes. 
Leaves 4’’—6”’ wide. 
Leaves ascending, spikelets %”’ long .. 22. P. sphaerocarpon. 
Leaves erect: spikelets scarcely %”’ long 23. P. erectifolium. 
Leaves scattered on the stem, linear-lanceolate or longer, erect, 1” 
—5’’ wide, all except the lowest narrowed to the base; branches of 
panicle ascending or at length spreading; spikelets 1’’—1%”’ long, 
very strongly nerved, nodes not barbed. 
Upper leaves not over 3”’ wide, middle leaves longest. 
Spikelets broadly obovate. 
Pubescence ascending, rigid ........ ... 24. P. Addisonii. 
Pubescence, if present, villous, spikelets nearly 14”’ 
IR oni) Stl te bi ag i, eget 2 25. P. consanguineum. 
Glabrous or nearly so, spikelets 1”’ WEE 26. P. neuranthum 
Spikelets elliptical, acntee 6... .2..'4s 27. P. angustifolium. 
Upper leaves 3’’—5’’ wide, much longer than the lower 28. P. 
Bicknellii. 
Low, densely tufted; leaves linear, 1’’—2’’ wide, erect, crowded near 
the base of stems, upper not reduced, narrowed to the base; branches 
of panicle erect or ascending; spikelets broadly elliptical or obovate, 
1”? or more long, nodes not barbed. 
Spikelets obovate, over 1%” long, second and third scales much 
teatree i iatt tie Pout hie. 4 2: ow 5 teehee 29. P. depauperatum. 
Spikelets elliptical, second, third and fourth scales equal. 
