GRASSES OF OHIO 
311 
Subfamily, Panicatae. 
Tribe, Paniceae. Panic-grass Tribe. 
Grasses having the 2-howered spikelets rounded or dorsally corn- 
pressed, jointed below the empty glumes, and arranged in racemes or 
panicles; lower dower staminate, vestigial or entirely absent; empty 
glumes membranous; dozvering glumes of the perfect dozver usually 
awnless, indurated, drmly enclosing the free grain. 
53. Panicum L. Panic-grass. 
Annual or perennial grasses of various habit with the spikelets 
in panicles. Spikelets 2-flowered, with 1 perfect flower and with 
a staminate or vestigial one below; empty glumes very unequal, the 
outer often minute; sterile lemma membranous often enclosing a 
hyaline palet; fertile lemma and palet indurated in fruit, margins of 
the lemma thick and inrolled; grain free, enclosed in the hardened 
flowering glumes. 
1. Basal leaves like those of the stem. 2 
1. Basal leaves unlike those of the stem. 10 
2. Basal leaf-sheaths compressed, often keeled. 3 
2. Basal leaf-sheaths round, little flattened, never keeled. 4 
3. Fruit stipitate; spikelets conspicuously secund. P. stipitatum. 
3. Fruit not stipitate; spikelets not conspicuously secund. P. agrostoides. 
4. Leaf-sheaths smooth. 5 
4. Leaf-sheaths pubescent; annuals. 6 
5. Outer empty glume about ^ as long as the spikelet; tall perennials with 
rhizomes. P. virgatum. 
5. Outer empty glume about ^ as long as the spikelet; annuals. 
P. dichotoinitlornm. 
6. Spikelets ovate, more than % in. long; spikelets close. P. miliaceum. 
6. Spikelets lanceolate or elliptic, less than % in. long; spikelets distant. 7 
7. Panicle narrow, the branches ascending; spikelets less than ^ in. long. 
P. dexile. 
7. Panicle spreading when mature; spikelet tV in. long or less. 8 
8. Panicle very large, usually the length of the plant. P, capillare. 
8. Panicle of medium size, usually the length of the plant. 9 
9. Stem delicate; leaf-blade less than Y in. wide. P. philodclphicmn. 
9. Stem stout; leaf-blade usually Y-ji in. wide. P. gattingeri. 
10. Leaf-blades way up the stem less than ^2 in. wide, attenuate to cordate 
at the base. 11 
10. Leaf-blades Y 2 way up the stem ^ in. or more wide, usually cordate clasp¬ 
ing at the base. 30 
11. Spikelets Y in. long or more. 12 
11. Spikelets less than Y in. long, usually about tV in. 22 
12. Leaves less than in. wide and about 18 times as long as wide. 
P. depaiiperatuin. 
12. Leaves more than Ya in. wide, and not elongated. 13 
13. Upper surface of the leaves glabrous. 14 
13. Upper surface of the leaves pubescent. P. leibergii. 
