130 GRAMINEAE (GKASS FAMILY) 



Panicles contracted. 



Rootstocks short or slender or none ; culms tufted or solitary. 

 Panicle not more than one-third the entire height of the plant. 

 Perennials. 



Spikelets 5 mm. long or more ; panicle dense. 

 Floret appressed-pubescent below. 



Lemma two-thirds as long as palea 1. S. clandeatinus. 



Lemma and palea subequal 2. S. canovirens. 



Floret glabrous 8. S. asper. 



Spikelets not over 4 mm. long ; panicle interrupted. 



Culms smooth ; ligule 0.5 mm. long 4. S. brevifolius. 



Culms minutely roughened by septae; ligule 2 min. long . 5. S. fiichardsonis. 



Annuals. 



Spikelets 4 mm. long ; lemma pubescent 6. S. vaginifiorus. 



Spikelets 2.5-3 mm. long; lemma glabrous 7. S. neglectus. 



Panicle one-third to one-half the entire height of the plant ... 8. S. indicus. 



Rootstocks stout, extensively creeping 9. S. virginicus. 



Panicles open (often contracted in no. 10). 

 Glumes very unequal. 



Spikelets 2.5-3 mm. long ; glumes ovate or lanceolate. 

 Sheaths bearded at the throat ; blades flat . . . . . . 10. S. cryptandrus. 



Sheaths not bearded ; blades involute . , \ i . . . . 11. 8. junceus. 



Spikelets 4-6 mm. long ; first glume awl-shaped ., , .... 12. S. heterolepis. 



Glumes subequal. 



Plants compressed at base ; leaves conduplicate 13. 8. compressus. 



Plants not compressed ; leaves flat 14. /S'. uniflorus. 



1. S. clandestinus (Spreng.) Hitchc. Tufted culms 4-12 dm. high; lower 

 leaves long, subrigid, the margins and involute-filiform tips scabrous; panicle 

 6-15 cm. long, often partially inclosed in the upper sheath ; spikelets 

 6-8 mm. long ; glumes unequal, acute, the first | the length of the 

 acute lemma, the second \ that of the long-acuminate pointed palea ; 

 lemma and palea appressed-pubescent toward the base, the lemma f 

 the length of the palea. (S. asper Man. ed. 6.) Sandy fields and 

 dry hills, Ct. to 111., Mo., and south w. Sept. FIG. 96. 



2. S. can6virens Nash. Similar to the preceding but smaller ; 

 the shorter leaves hirsute near the base; panicle smaller; spikelets 

 about 6 mm. long ; lemma and palea acute, subequal. Sandy soil, 

 Tenn., Mo., and south w. 



3. S. asper (Michx.) Kunth. Culms stout, 3.5-10 dm. high ; 

 96. S. eland, sheaths overlapping ; blades neaily as long as the culm, the upper 

 SpikeletxS. exceeding the panicle, pilose above at the flat base, the long involute- 

 filiform tip scabrous; terminal panicle 8-25 cm. long, partly in- 

 cluded in the inflated upper sheaths, lateral panicles small, usually hidden in 

 the sheaths, or none; spikelets 5-6 mm. long; glumes unequal, obtuse or sub- 

 acute, the first about \ as long as the floret ; lemma and palea glabrous, the 

 lemma slightly the longer. (S. longifolius Wood.) Dry 



sandy soil, Me. to S. Dak., and southw. FIG. 97. 



4. S. brevif61ius (Nutt.) Scribn. Tufted culms 3-6 dm. 

 high, very slender ; leaves in volute- filiform ; ligule 0.5 mm. long, 

 erose-truncate ; panicle very slender, loosely flowered,, 5-10 cm. 

 long ; spikelets about 4 mm. long ; glumes acuminate, subequal, 

 f as long as the short-cuspidate lemma, which slightly exceeds 

 the palea. (S. cuspidatus Wood.) Dry open ground, Wis. 

 to Mo. , and westw. 



5. S. Richardsdnis (Trin.) Merr. Similar to the preceding, 



2-5 dm. high ; culms erect or ascending from a slender horizontal rootstock, 

 minutely roughened by septae ; ligule 2 mm. long, acute ; panicle 1-6 (rarely 10) 

 cm. long; spikelets somewhat crowded, 3 mm. long; glumes acute, less than 

 \ as long as the cuspidate lemma (the cusp about 1 mm. long) which exceeds 

 the palea. (8. cuspidatus, in part, and S. depauperatus Man. ed. 6; JS. brevi- 

 folius Nash, as to description, not Scribn.) Meadows and along rivers, N. B. 

 and Me. ; Neb., and in the far West. Aug. 



6. S. vaginiflbrus (Torr.) Wood. Tufted culms 2-6 dm. high, slender^ 

 erect to widely spreading ; leaves about 2 mm. wide, involute toward the end \ 

 panicles numerous, partially included in the inflated sheaths, or the terminal 



