Jones: Flora of Illinois, 22. Gramineae 53 



5. Lemmas not webbed; nerves of the lemma pubescent; spikelets 6-8 



mm. long; moist woods, rare P. autumnalis Muhl. 



l.Low tufted annuals; stems 5-25 cm. tall. 



10. Lemmas distinctly 3 -nerved, the other nerves obscure; lemmas webbed at 



the base; anthers 0.2-0.3 mm. long; dry ground. May-Aug 



P. chctpmaniana Scribn. 



10. Lemmas 5-nerved, not webbed at the base; anthers 0.7-1 mm. long; 

 common in waste places, lawns, cultivated ground; nat. from Eurasia. 

 May-Oct P. annua L. 



6. Briza L. — Quaking Grass 

 B. maxima L. Fields and waste places, occasional; adv. from Eurasia. 



7. Eragrostis Host 



1. Stems creeping, rooting at the nodes, the flowering branches erect; plants 

 annual. 



2. Lemmas 1.5-2 mm. long; anthers 0.2-0.3 mm. long; flowers perfect; sandy, 

 gravelly, or muddy shores. July-Oct E. hypnoides (Lam.) BSP. 



2. Lemmas 3-4 mm. long; anthers 1.5-2 mm. long; plants dioecious; sandy 



soil, not common E. reptans (Michx.) Nees 



1. Stems erect or ascending, not rooting at the nodes. 



3. Spikelets 2-7- flowered, 2-4 mm. long. 



4. Panicle about as long as wide, the branches elongated, capillary; plants 



branched at the base; dry ground in open woods. July-Sept 



E. capillaris (L.) Nees 



4. Panicle much longer than broad, the branches short; plants branched 



from above the base; sandy soil and roadsides. Aug. -Oct 



E. jrankn C. A. Mey. 



3. Spikelets 5-35-flowered, 3-15 mm. long. 



5. Plants perennial, erect, 30-120 cm. tall. 



6. Panicle-branches spreading at maturity; spikelets 6-12-flowered; lem- 

 mas 1.5-2 mm. long; sandy soil. July-Oct. [£. pectinacea of auth., 

 not (Michx.) Nees} E. spectabilis (Pursh) Steud. 



6. Panicle-branches erect or ascending; spikelets 4-6-flowered; lemmas 



2.5-3 mm. long; sandy soil, chiefly in centr. and w. 111. [£. pilifera 



Scheele] E. trichodes (Nutt.) Wood 



5. Plants annual, usually 10-50 cm. tall, decumbent at base. 



7. Keels of glumes and lemmas with minute glands; spikelets 8-35- 



flowered. 

 8. Spikelets 2.5-3 mm. wide; waste places and cult, ground; nat. from 



Eur. Stink Grass. June-Sept. \_E. megastachya Link} 



E. cilianensis (All.) Link 



8. Spikelets 1.5-2 mm. wide; waste places and cult, ground; nat. from 

 Eur. [£. minor Host} E. poaeoides (L.) Beauv. 



