94 



GRAMINEAE (GRASS FAMILY) 



§ 1. SCHIZACHYRIUM (Nees) Trin. Bacemes solitary; joints of the rhachis 



clavate. 



1. A. scoparius Michx. Culms tufted, 4-12 dm. high ; 

 branches single or in pairs from the upper sheaths ; sheaths 

 glabrous or hairy ; blades often hairy above near the base ; 

 racemes slender, 2-6 cm. long, joints and sterile pedicels 

 hairy on the margins ; sterile spikelet a single awn-pointed 

 glume, 2-4 mm. long ; fertile spikelet about 7 mm. long ; 

 awn bent and twisted. — Dry ground, N. B. to Sask., and 

 south w. July-Sept. Fig. 50. 



Var, littoralis (Nash) Hitchc. Culms in large tufts ; the 

 innovations and lower sheaths strongly compressed, glaucous. 

 50. A. scoparius. (A. littovalis Nash.) — Sand dunes along the coast, N.Y. and 

 Two spikelets x ly^. SOUthw. 



§ 2. CAMPYLOMf SCHUS Fourn. Bacemes in fascicles of 2-6 ; joints of the 



rhachis not clavate. 



* Pedicellate spikelet sterile^ consisting of\-2 glumes or reduced to a pedicel. 



•^ Sp allies equaling or exceeding the racemes; sheaths keeled. 



2. A. glomeratus (Walt.) BSP. Culms stout, 0.5-1.5 m. high, leafy; sheaths 

 usually sparsely hirsute ; inflorescence bushy-branched at the summit of the culm; 

 spathes very scabrous; racemes 2; the slender joints of the 

 rhachis and the sterile pedicel clothed with long silky hairs. 

 (A. macrourus Michx.; A. corymbosus Nash.) — Sandy 

 ground near the coast, Mass. and southw. Sept., Oct. 



3. A. virginicus L. Culms rather slender^ 5-12 dm. high, 

 sparingly branched above ; sheaths smooth or somewhat hir- 

 sute on the margin ; blades usually hirsute above near the 

 base ; spathes smooth ; racemes 2 or 3, slender ; hairs long 

 and silky. — Open ground, Mass. to 111., Fla., and Tex. 

 Fig. 51. 



t~ +~ Bacemes, or some of them, on peduncles exserted beyond 

 the spathes. 



4. A. Elli6ttii Chapm. Culms in tufts, flattened at base, 

 5-10 dm. high ; lower sheaths and leaves appressed-hirsute 

 or becoming nearly glabrous, upper sheaths aggregated and 

 much enlarged; racemes usually 2, very slender, flexuous, 

 softly and loosely silky; spikelets 4 mm. long. — Dry sandy 

 or gravelly soil, Del. to Mo., and southw. Sept., Oct. 



5. A. ternarius Michx. Culms some- 

 what stouter and taller than in the pre- 

 ceding ; sheaths usually smooth, the upper ^^ ^ virginicus 

 sheaths not crowded nor enlarged (or the Three spikelets x22/. 

 upper one only somewhat enlarged) ; ra- 

 cemes 2 or 3, stouter, more strict, densely silky; spikelets 

 6 mm. long, {A. argyraeus Schultes.) — Dry sandy soil, 

 Del. to Tenn., and southw. Aug. -Oct. 



* * Pedicellate spikelet staminate ; racemes 2-6 on a long 

 exserted peduncle; rhachis-joinis stout. 



6. A. furcatus Muhl. Culms robust, in large tufts, 

 1-1.5 m. high, branching from the upper nodes; sheaths 

 glabrous ; blades elongated, 4-8 mm. wide, scabrous on the 



margins and often hirsute on the upper surface near the base ; racemes 5-12 cm. 

 long, stout, usually purplish ; rhachis-joints and pedicels hairy on the sides and 

 at the summit ; sessile spikelets 8-9 mm. long ; staminate spikelet slightly longer. 

 — Dry open ground, Me. to Sask.. and southw. Fig. 52. 



A. furcatus x 1^^. 



