74 American Midland Naturalist Monograph No. 2 



12. Bristles scarcely exceeding tbe achene; leaves 6- 16 mm. wide; 

 spikelets 4-8 mm. long, several to many in dense glomerules; 



along ditches, streams, and lake shores, throughout 111 



S. atrovirens Willd. 



10. Bristles smooth, 6, flexuous. 



13. Bristles scarcely exceeding the glumes; spikelets cylindrical, 6-8 

 mm. long; leaves 5-10 mm. wide; wet ground in woods, or along 

 ditches, common S. lineatiis Michx. 



13. Bristles at maturity much longer than the glumes; spikelets sessile 

 in glomerules of 3-15; leaves 4-6 mm. wide; wet ground, locally 



abundant, sometimes covering large areas 



S. cyperiniis (L.) Kunth 



10. Eriophorum L. — Cotton Sedge 



1. Leaves 1-1.5 mm. wide; involucral bract short, erect. 



2. Blade of the upper stem-leaf not longer than the sheath; swamps and 



bogs, Peoria, Brendel; Woodford Co., McDonald in 1887 



E. gracile Roth 



2. Blade of the upper stem-leaf much longer than the sheath; bogs, rare; 



Beardstown, Cass Co., Geyer E. tenelluyn Nutt. 



1 . Leaves broader, 2-6 mm. wide; involucral leaves 2 or more. 



3. Glume of the spikelets with several striations or ribs; stamen 1; plants 



flowering in July and Aug.; not uncommon in Lake Co 



E. virginiciim L. 



3. Glume with midvein prominent; stamens 3; plants flowering in May and 

 June. 

 4. Midvein of glume extending to the apex; upper leaf-sheaths not dark- 

 girdled at the summit; bogs in n. Ill 



E. viridicar'tnatum (Engelm.) Fern. 



4. Midvein of glume not extending to the tip; upper leaf-sheaths dark- 

 girdled at the summit; bogs, n.e. Ill E. angnstifolitim Honck. 



11. Rhynchospora Vahl — Beaked-rush 



1. Bristles downwardly barbed, or sometimes smooth. 



2. Glumes whitish; bristles 9-15; bogs, Lake Co., Gleason & Shobc 137; 

 Peoria, Brendel R. Ma (L.) Vahl 



2. Glumes brown; bristles 6. 



3. Leaves filiform, less than 0.5 mm. wide; spikelets 3-6 in a terminal 



cluster; bogs and springy ground, n. III., rare R- capillacea Torr. 



3. Leaves linear, 4-7 mm. wide; spikelets numerous in clusters or heads; 



lake shores, and moist ground; Cook Co., Hill in 1906; Kankakee 



Co., Hdl in 1871, Sherff 1656. [R. glomcrata sensu auth.} 



R. capitellata (Michx.) Vahl 



1. Bristles upwardly barbed; leaves flat, 1-4 mm. wide; spikelets ovoid, sessile, 



in erect cymose clusters; wet sandy soil, Kankakee Co., Hdl in 1871 



R. cymosa Ell. 



