9i 



GRAMIXEAE (GRASS FAMILY) 



§ 1. SCHIZACHYRIUM (Nees) Trin. Racemes 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 

 southw. July-Sept. Fig. 50. 



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

 innovations and lower sheaths strongly compressed, glaucous. 

 (A. littoralis Nash.) — Sand dunes along the coast, N. Y. and 

 southw. 



50. A. scoparius. 

 Two spikelets x 1%. 



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



rhachis not clavate. 



* Pedicellate spikelet sterile, consisting of 1-2 glumes or reduced to a pedicel. 



-t- Spathes 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. 



51. A. virffinicus. 



•*- -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 

 sheaths not crowded nor enlarged (or the Three snikere't 

 •upper one only somewhat enlarged) ; ra- 

 cemes 2 or 3, stouter, more strict, densely silky; s)rikelets 

 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-joints stout. 



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

 52 A. furcatus X iV 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 8-0 mm. long ; staminate si)ikelet slightly longer. 

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



