24 | JOURNAL, OF THE 
to thirty. This paper is only intended to cover the re- 
gion between northern Florida and Indian Territory, 
and Minnesota and Maine. The dichotomous group can 
be characterized as follows: 
Basal leaves different from those of the stem, broader, and generally 
shorter (except in a few species) ; spikelets all pediceiled. not racemose 
onthe branches, neither gibbous at base, awned, or warty. Stems 
erect, prostrate, or decumbent, at first simple, later (except in a few 
species) dichotomously or fasciculately branched, producing on the 
branches smaller leaves and smaller panicles. 
In the following paper seventy-four species are enumerated, nat the 
real number is probably even in excess of this. 
KEY TO THE EASTERN DICHOTOMOUS SPECIES OF PANICUM. 
bed 
(? = one inch. = one twelfth of an inch. ° = one foot.) 
Leaves lanceolate or ovate-lanceolate, clasping by a broadly cordate 
base spikelets 14” long or more; ligule a mere margin. 
Largest leaves about 1’ wide, panicle spreading. 
Spikelets obovate, over 1%”’ long. 
Dare PHINCUL FL. ab ie apa ale x Bim bees te 1. P. Porterianuim. 
NOGeS PIA DLOUS «i. paced webs 4s 2. P. macrocarpon. 
Spikelets elliptical, 14’’ long 
Leaves ovate-lanceolate, 2’— 3’ long, ciliate, sheaths soft- 
PUIBCSHCBGY oki Lae 3. P. commelinaefolium, 
Leaves lanceolate, 3’ long or more, sheaths papillose- 
oo AO Rage Caen ado sate 4. P. clandestinum. 
Largest leaves narrower, 5’’—8’’ wide, ligule none. 
Spikelets 14” long. 
Stems erect, sheaths clasping ....... 5. P. commutatum., 
Stems decumbent or ascending, sheaths loose 6. P. Joorii, 
Spikelets 134”? long, elliptical, plant decumbent 7. P. Mana- 
tense. 
Leaves rounded at base, lanceolate or narrower, 4’’—8” wide, spike- 
lets over 14%”’ long. 
Branches of panicle erect, leaves glabrous, ligule none. 
Sheaths sparingly papillose-hispid .... 8. P. xanthophysum. 
miteaths tlre eet atic es hae ede tte ow 9. P. calliphyllum., 
Branches of panicle spreading, ligule pilose. 
Panicle 3’—S’ long, spikelets elliptical, numerous 10. P. scab- 
riusculum. 
Panicle 2’—3’ long, branches and obovate spikelets few, 
leaves PUERCO Ss seu smtiids on oe eos 11. P. scopariuin. 
Leaves narrower, 3’’—5’’ wide, somewhat rounded at the base, spike- 
lets 14 ”’—2” long. 
Ligule pilose. 
Notlés barbed i279. us: sens sore ae 12. P. malacophyllum, 
