Panicum 



Paniceae 



165 



Jan. 



Feb 



Mar 



Apr. 



May 



June 



July 



Aug. 



Sept. 



Oct 



Nov 



Dec 



Miles 



50 



Map 298 



Panicum praecocius Hitchc. & Chase 



pubescent; second glume and sterile lemma 5-7-nerved or 7-9-nerved on 



large spikelets. 



i 



Plants grayish, velvety-pubescent; spikelets 1.3-1.4 mm long 24. P. auburne. 



Plants pubescent, often villous but not velvety. 



Culms conspicuously pilose with long, horizontal hairs 4-5 mm long, and branching 

 before the expansion of the primary panicles; spikelets mostly 1.8-1.9 mm long. 



25. P. praecocius. 



Culms variously pubescent, if pilose the hairs appressed or some widely spreading, 

 less than 4 mm long; culms not branching before the expansion of the 

 primary panicles. 

 Spikelets less than 2 mm long. 



Vernal blades glabrous or nearly so above (6-10 cm long and 5-10 mm wide) ; 



spikelets 1.5-1.7 mm long 26. P. tennesseense. 



Vernal blades pubescent above or if glabrous smaller than the preceding, some- 

 times pilose near the base and margins only. 

 Spikelets 1.3-1.5 mm long. 



Upper surface of blades puberulent as well as long-villous 



27. P. albemariense. 



Upper surface of blades villous but lacking the short, appressed pubescence ; 

 vernal plants usually purplish with erect leaves, autumnal plants 

 usually greenish; nodes with short hairs, if bearded. 

 Sheaths papillose-pilose with no short, appressed pubescence in the 

 spaces between the nerves; lower surface of blades with a subap- 

 pressed, papillose pubescence and lacking a short, appressed 

 pubescence; axis of panicle generally pilose, the lowest panicle- 

 branches spreading and tangled 28. P. implicatum. 



Sheaths more or less softly papillose-pilose, some or all of them with a 

 short, appressed pubescence on the spaces between the nerves; 

 blades erect; lower surface of the blades more or less short ap- 

 pressed-puberulent, in addition to a longer pubescence; axis of 

 panicle generally puberulent, the lowest panicle-branches ascending 



and not tangled 29. P. meridionale. 



Spikelets 1.6-1.9 mm long; plants green, rarely purplish; nodes mostly bearded, 



usually with long, spreading hairs. 



Pubescence on upper surface of vernal blades short-pilose, rarely long-pilose, 



appressed at least on the apical half (rarely not appressed); nodes 



usually densely pilose with spreading hairs; spikelets rarely less than 



