18 GRAMINEAE 



panicle branches appear spike-like : spikelets hispid. — Common in 

 ditches and waste places. An occasional form is almost awnless. June- 

 October. 



2. P. agrostoides Spreng. Flat culms erect, 2°-3° high, branching : 

 panicles 3'— 5' long : primary panicle-branches spreading, secondary ap- 

 pressed : spikelets numerous, crowded, f" long : second and third scales 

 equal, twice as long as the first, and longer than the fourth. Our plant 

 Is provided with long capillary involucral hairs at the base of the spike- 

 let. — In swampy grounds. Near Adams (rare) and at Fish Lake. 

 July-September. 



3. P. Porterianum Nash. 1°- 3° high : larger leaves 4' long and 1' 

 wide, cordate-clasping at base, more or less hairy : nodes barbed : sheaths 

 hairy : panicle 2'-4' long, with ascending branches : spikelets IJ" long 

 or more, hairy. — Frequent in rich woods. May-July. 



4. P. macrocarpon Le Conte. Like the last, but nodes not barbed, 

 sheaths glabrous, and leaves not hairy, but ciliate : spikelets more in- 

 flated. — Frequent in rich woods. May-July. 



5. P. clandestinum L. 2°-5° high : sheaths very papillose-hispid : 

 spikelets about IJ" long, smoothish : second and third scales plainly 

 9-nerved. In damp thickets. Not uncommon. May-July. 



6. P. Scribnerianum Nash. l°-2° high, growing in clumps: leaves 

 spreading, 2'-4' long, 3"-4''' wide, rough : sheaths papillose-hispid : 

 culms and panicle smooth : panicle open, 2'- 3' long, l'-2' wide. — Com- 

 mon in dry woods. May-July. 



7. P. Liebergil (Vasey) Scribn. Resembles the last but is more 

 slender and with ascending leaves, hairy beneath : sheaths very pubes- 

 cent : panicle much exserted, 2'-3' long : spikelets about IJ" long, 

 noticeably pubescent. — Common on prairies near Lee's Summit. Also 

 at Buckuer. May-June. 



8. P. sphaerocarpon Ell. Culms i'-W high, at length much- 

 branched, smooth : leaves W-Z' long, 2"-3" wide, smooth or sparingly 

 long-ciliate at the clasping base : sheaths ciliate on margin : primary 

 panicle 2' long, much exserted : spikelets glabrous, xy long. — Sandy 

 woods southeast of Grain Valley. June-July. 



9. P. unciphyllum Trin. Culms 6'-10' high, at length much- 

 branched : leaves 2'-3' long, 2''-3'' wide, papillose-hairy on both sides 

 and long-ciliate : sheaths and culms long-hairy and nodes densely 

 bearded : primary panicle l'-2' long, little or not at all peduncled : 

 spikelets less than I" long, pubescent. — On dry prairies south of Lee's 

 Summit, and in dry woods at Swope's Park. May-June. 



10. P. lanuginoBum Ell. Culms 12'-18' high : leaves U'-3' long, 

 2"-4" wide, hairy and sparingly ciliate : sheaths, culm and main 

 branches of the panicle long-hairy : panicle lY-Z' long : spikelets J" 

 long, pubescent. — Common in dry woods throughout. May- July. 



