152 Paniceae Panicum 



Ligules not more than 2 mm long. 



Spikelets nearly spherical at maturity, less than 1.8 mm long; blades 



glabrous, firm, cordate 13. Sphaerocarpa, p. 170. 



Spikelets elliptic or obovate, more than 1.7 mm long (except in P. 

 columbianum) . 

 Blades not cordate at the base. 



Spikelets less than 3 mm long 12. Columbiana, p. 169. 



Spikelets more than 3 mm long 14. Oligosanthia, p. 171. 



Blades cordate at the base. 



Spikelets 2.5-2.9 mm long 15. Commutata, p. 172. 



Spikelets 3-5 mm long 16. Latifolia, p. 173. 



KEY TO THE INDIANA SPECIES OF PANICUM 



A. Spikelets glabrous. 



Spikelets 3 mm long or longer. 

 Annual. 



Spikelets 4-5 mm long and more than 1.8 mm wide. (See excluded species no. 



82, p. 1030.) P. miliaceum. 



Spikelets 3-4 mm long, less than 1.8 mm wide 2. P. flexile, p. 157. 



Perennial. 



Panicles 20-40 cm long; spikelets gaping or curved at the apex. 

 Ligules 2-4 mm long; first glume two thirds to three fourths as long as the 



spikelet 6. P. virgatum, p. 158. 



Ligules less than 1 mm long; first glume a third to half as long as the 



spikelet 7. P. anceps, p. 159. 



Panicles 3-8 cm long; spikelets not gaping or curved at the apex. 



Blades elongated, not over 5 mm wide and more than 20 times as long as 



wide; spikelets beaked or pointed at the apex. .11. P. depauperatum, p. 160. 



Blades not elongated, less than 20 times as long as wide; spikelets blunt at 



the apex 43. P. Scribnerianum, p. 171. 



Spikelets less than 3 mm long. 



Spikelets warty 10. P. verrucosum, p. 159. 



Spikelets not warty. 



Annual; basal leaves similar to those of the culm; plants not forming winter 

 rosettes; panicles more than 12 cm long (except in depauperate plants). 

 Sheaths glabrous. 



Spikelets 2-3.5 mm long, usually about 2.9 mm long (rarely a few as short 

 as 2 mm), acute; plants usually large and spreading, 50-100 cm long. 



1. P. dichotomiflorum, p. 156. 



Spikelets 1.8-2.2 mm long, usually about 2 mm long, blunt; plants shorter 



and more slender than the preceding 



la. P. dichotomifloruvi var. puritanorum, p. 156. 



Sheaths pubescent. 



Pulvini of the panicle hispid. 



Panicles included at the base, usually large, about as wide as long, gen- 

 erally about half as long as the whole plant; blades thickly papillose- 

 hispid above and beneath 3. P. capillare, p. 157. 



Panicles exserted, ovoid, usually not as large as the preceding, about a 

 third as long as the whole plant; blades sparsely hirsute above and 



beneath 4. P. philadelphicum, p. 157. 



Pulvini of panicle glabrous 5. P. Gattingeri, p. 157. 



Perennial; basal leaves not like those of the culm; plants forming winter 

 rosettes; panicles not over 12 cm long, except those of Panicum agrostoides 

 which are much longer. 

 Pedicels mostly about half as long as the spikelets; spikelets subsecund on 



the lower side of the branchlets of the inflorescence 



9. P. agrostoides, p. 159. 



