68 American Midland Naturalist Monograph No. 2 



joints of the rachis clavate; sandy or prairie soil and open woods. Aug.- 



Oct. Little Bluestem A. scoparius Michx. 



1. Racemes in fascicles of 2-7, the common peduncle enclosed in a bract-like 

 sheath or spathe; joints of the rachis not clavate. 

 2. Pedicellate spikelet staminate, as large as the sessile spikelet; racemes 5- 

 13 cm. long, exserted on a naked peduncle, the uppermost sheath in- 

 conspicuous, not inflated; rachis straight, the hairs inconspicuous and 

 shorter than the spikelets; stamens 3; prairie soil. July-Sept. [A. provin- 



aalis Lam.} Big Bluestem A. furcatus Muhl. 



2. Pedicillate spikelet reduced to 1 or 2 empty glumes or a m'ere pedicel; 

 racemes L5-4 cm^. long, from a broad, conspicuous, usually inflated 

 spathe; rachis flexuous, the hairs as long as or longer than the spikelets; 

 stamen 1; fields and roadsides in the s. half of the state. Sept. -Oct. 

 Broom-sedge A . virginicus L. 



66. Erianthus Michx. 



E. alope cur aides (L.) Ell. Plume Grass. Open woods, s. 111., rare. Jackson 

 Co., French in 1878; Union Co., Mulcaster in 1935. [E. divarkatus (L.) 

 Hitchc] 



67. Sorghum Pers. 



1. Perennial with creeping rhizomes; spikelets readily deciduous at maturity; 

 pedicellate spikelet usually staminate; fields and waste places, escaped 

 from cult.; introd. from Eur. June-Oct. \^Holcus halepensis L.] Johnson 

 Grass S. halepeyise (L.) Pers. 



1. Annual; spikelets persistent at maturity; pedicellate spikelet usually neutral, 

 shorter than the sessile one; waste places, occasionally escaped from cult.; 

 resembling Z^ea mays when not in bloom. [^Holcus sorghum L.; Sorghum 

 saccharatum Moench] Sorghum S. vulgare Pers. 



68. SORGHASTRUM Nash 



S. nutans (L.) Nash. Indian Grass. Prairies, open woods, roadsides. Aug.- 

 Oct. 



69. Tripsacum L. 



T. dactyloides L. Gama Grass. Wet ground, rare, chiefly in the s. half of 

 the state. May-Sept. 



70. Zea L. Maize. Indian Corn 

 Z.- mays L. Cult., and rarely spontaneous. July-Sept. 



23. Cyperaceae J. St. Hil. — Sedge Family 



1 . Spikelets all alike; flowers of the spikelet, or at least one of tiiem perfect. 

 2. Glumes of the s[)ikelet 2-ranked; spikelets flattened or subterete. 



3. Perianth bustles none; s[)ikclets in umbellate clusters; stems mostly triangular. 



4. Spikelets several-many-f]owered ; glumes many 1. Cvperus 



4. Spikelets 1 -flowered; glumes 2-4 2. Kpllingia 



3. Perianth of 6-9 bristles; Inflorescence axillary; stem te»ete, hollow; achenes 



beaked 3. Diilichhim 



2. Glumes spirally imbricated. 



5. Spikelets with several to many perfect flowers. 



