348 
The Ohio Naturalist. 
[Vol. XIV, No. 8, 
11. Spikelets Y inch long or more. 12. 
11. Spikelets less than Ys inch long, usually about ys inch. 22. 
12. Leaves less than ys inch wide and about IS times as long as wide. 
Panicum depauperation. (10). 
12. Leaves more than Y inch wide, and not elongated. 13. 
13. Upper surface of the leaves glabrous. 14. 
13. Upper surface of the leaves pubescent. Panictim leibergii. (24). 
14. Outer empty glume J as long as the spikelet. short acute. 
Panicum scribnerianum. (25). 
14. Outer empty glume Y 2 as long as the spikelet, long acuminate. 
Panicum xanthophysum. (26). 
15. Stem simple or with basal branches only. 16. 
15. Stem at length faciately branched. 22. 
16. Hairs on the leaf sheath almost an Y inch long or longer, spreading, 
usually dense. Panicum linearifolium. (11). 
16. No hairs on the leaf sheath, or with hairs less than ys inch long, 
sometimes ciliate on the margin. 17. 
17. Leaf blade ^ inch or less wide, usually 18 or more times as long 
as wide; spikelets usually glabrous. 18. 
17. Leaf-blade usually much more than Y inch wide, never more than 
8 times longer than wide; spikelets more or less pubescent. 20. 
18. Leaves much elongated; often 6 to 10 inches long, attenuate at the 
base. Panicum werneri. (12). 
18. Leaves not elongated; generally less than 3V£ inches long, not at¬ 
tenuate at the base, spikelet less than Y inch. 
Panicum bicknellii. (13). 
19. Spikelets roundish, not over ^ inch long. 20. 
19. Spikelets oblong-eliptic oreliptic, usually ^ inch or more long. 21. 
20. Nodes pubescent with appressed hairs, base of the leaves ciliate, 
panicle near’y as wide as long. Panicum sphaerocarpon. (14.) 
20. Nodes glabrous, base of the leaves not ciliate, panicle not more than 
Y wide as long. Panicum polyanthes. (15). 
21. Stems pubescent. Panicum tsugetorum. (23). 
21. .Stems glabrous. Panicum boreale. (18). 
22 . Spikelets glabrous. 23. 
22. Spikelets pubescent. 24. 
23. Nodes densely bearded. Panicum microcarpon. (17). 
23. Nodes not bearded. Panicum dichotnmum. (16). 
24. Ligule at the top of the leaf sheath minute or absent. 25. 
24. Ligule present. 26. 
25. Nodes of the main stem glabrous or with a few hairs. 
Panicum boreale. (18). 
25. Nodes of the main stem crisp pubescent. 
Panicum ashei. (27). 
26. Upper sheaths glabrous (ciliate on the margin). 
Panicum lindheimeri. (19). 
26. All of the sheaths pubescent. 27. 
27. Upper surface of the leaves glabrous, except for a few long hairs 
near the base. Panicum tsugetorum. (23). 
27. Upper surface of the leaves pilose. 28. 
28. Outer empty glume acute; spikelet rg inch long pubescence on the 
sheath more than ys inch long. Panicum villosissimum. (21). 
28. Outer empty glume blunt; spikelet less than ys inch long; pubes¬ 
cence on the sheaths not so dense and less than ys inch long. 29. 
29. Upper surface of the leaf-blade long-pilose; plants yellowish-green. 
Panicum hauchucae. (20). 
29. Upper surface of the leaf-blade long-appressed pubescent. 
Panicum implicatum. (22). 
