30 POACEAE. 



long: panicle loose and open, 1.5-4 dm. long: gjiikelets numerous, 5-8-flowered, 

 7-10 mm. long; empty scales acute, 1-nerved; flowering scales about 4 mm. 

 long, the apex 2-tootlied between the excurrent nerves. [Triodia cuprea Jacq.] 

 — ■ Common, on roadsides, and in fields and fence rows. — Sum. — Tall red-top. 



37. ERAGROSTIS Beauv. Low or tall annual or perennial tufted rarely 

 dioecious grasses, the stems sometimes prostrate or creeping, with flat or convo- 

 lute leaf-blades and open or contracted panicles. Spikelets numerous, arranged 

 singly or in fascicles, 2-many-flowered, the flowers perfect or unisexual. Scales 

 4^many, membranous, compressed, keeled, the 2 lower empty, unequal, the 

 remaining scales larger, 3-nerved, obtuse or acute at the apex; palet shorter 

 than the scale, prominently 2-nerved or 2-keeled, often incurved and persistent 

 on the rachilla after the fall of the scale. Stamens 2 or 3. Styles distinct, 

 short. Stigmas plumose. 



Stems not creeping : flowers perfect. 

 Annuals. 



Spikelets 2-5-flowered. 



Pedicels and branches of the panicle short : stems usually branched above. 



1. E. Frankii. 

 Pedicels and branches of the diffuse panicle long 



and capillary : stems branched only at the base. 2. E. capillaris. 



Spikelets more than 5-flowered. 



Spikelets 1.5 mm. wide or less : palets remaining 

 attached to the continuous rachls for some time 

 after the flowering scales have fallen. 

 Flowering scales thin, usually bright purplish, 

 the lateral nerves faint or wanting : spikelets 

 about 1 mm. wide. 3. E. pilosa. 



Flowering scales firm, usually dull purple or green, 

 the lateral nerves very prominent : spikelets 

 about 1.5 mm. wide. 4. E. Purshii. 



Spikelets exceeding 2 mm. wide : palets falling with 

 the flowering scales and the internodes of the 

 rachis. 5. E. major. 



Perennial. 6. E. pectinacea. 



Stems creeping, rooting at the nodes. 7. E. hypnoides. 



1. E. Frankii Steud. Stems 1.5-4 dm. tall : leaf -blades 5-13 cm. long, 2-4 mm. 

 wide: panicle 5-15 cm. long, open: spikelets ovate, 2-3 mm. long, 3-5-flowered, 

 the flowering scales acute, the lower ones 1.5 mm. long, their lateral nerves 

 obscure. — Lower Susquehanna valley. Eare, on sandy shores and islands. — 

 Fall. 



2. E. capillaris (L.) Nees. Stems 2-5 dm. tall, slender: leaf -blades 7-25 cm. 

 long, 2-4 mm. wide: panicle diffuse, 1-4 dm. long: spikelets ovate, 2-3 mm. 

 long, 2-4-flowered, the flowering scales acute, 1.5 mm. long, their lateral nerves 

 obscure. — Rather common, in dry soil. — Sum. and fall. 



3. E. pilosa (L.) Beauv. Stems 1.5-5 dm. tall: leaf -blades 2-13 cm. long, 

 2 mm. wide or less: panicle 5-15 cm. long, its branches finally spreading, often 

 hairy in the axils: spikelets 5-12-flowered, 3-6 mm. long, about 1 mm. wide, 

 the flowering scales acute, the lower ones 1.5 mm. long, thin. — Eather com- 

 mon, in cultivated grounds and waste places. Nat. of Eu. — Sum. and fall. 



4. E. Purshii Schrad. Stems 1.5-5 dm. tall: leaf-blades 3-9 cm. long, 2 mm. 

 wide or less: panicle 7-20 cm. long, open, naked in the axils: spikelets 5-15- 

 flowered, 3-8 mm. long, about 1.5 mm. wide, the flowering scales acute, firm, 

 the lower ones 1.5 mm. long. — Susquehanna valley. Eather rare, on the river 

 shore. — Sum. 



5. E. major Host. Ill-scented. Stems 1.5-6 dm. tall: leaf -blades 5-1& cm. 

 long, 2-6 mm. wide: panicle 5-15 cm. long: spikelets 8-35-flowered, 5-16 mm. 

 long and about 3 mm. wide, the flowering scales obtuse, 2-2.5 mm. long, the 

 lateral nerves prominent. [E. megastachya Link.] — Common, in waste places 

 and cultivated grounds. Nat. of Eu. — Sum. and fall. 



