146. Graminkae 333 



thickets, common nearly throughout 111. May- 

 July. Woodland Blue Grass P. sylvestris A.Gray 



8. Spikelets 5-6 mm long; lemmas 3.5-4 mm long, gla- 

 brous between the nerves; known In 111. onlv from 

 three nineteenth-century collections; Fulton and 



Peoria counties, Breridel; Hancock Co., Mead 



P. wolfii Scribn. 



5. Lemmas not webbed, 5-nerved, pubescent on the nerves 



and between them; spikelets 5-7 mm long; moist woods, 

 rare P. autumnalis Muhl. 



1. 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; fields and 

 roadsides, locally abundant nearly throughout 111. Apr. -June 

 P. chapmaniana 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. Apr. -Oct. Annual Blue Grass 



P. annua L. 



8. Briza L. — Quaking Grass 



B. maxima L. Fields and waste places, rarely escaped from cult.; 

 adv. from Eurasia; Cook Co. 



9. Eragrostis Beauv. 



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 per- 

 fect; sandy, gravelly, or muddy shores. July-Oct. Pony Grass 

 E. hypyioides (Lam.) BSP. 



2. Lemmas 3-4 mm long; anthers L5-2 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- to 7-flowered, 2-4 mm long. 



4. Panicle about as long as wide, the branches elongated, capil- 

 laiy; 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. jrankii C.A.Mey. 



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



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



6. Panicle-branches spreading at maturity; spikelets 6- to 12- 



flowered; lemmas 1.5-2 mm long; sandy soil. July-Oct. 

 Tumble Grass. [E. pectinacea sensu auth., non (Michx.) 

 Nees] E. spectabilis (Pursh) Steud. 



