618 CLXL GRAMINEjE. Atheropogon, 



closely imbricate, smooth; upper glume 5- veined; fr. dark brown. — (I) Common 

 about houses, foot-paths, &c., Mid. and W. States. Aug. 



47. CYNODON. Rich. 

 <rf. KVbyv, adog, o^oj, tooth; alluding to the singular, one-sided spikelefs. 



Spikes digitate or fasciculate ; spikelets unilateral, in a single row ; 

 glumes membranaceous, shorter than the flowers, persistent ; 9 upper 

 palea bifid-toothed ; rudiment minute, pedicellate, in a groove of the 

 upper palea ; scales truncate. 



C. Dactylon. Pers. (Digitaria. Ell. Panicum. Linn.) Berjnuda Grass. 

 Rt. creeping extensively ; st. creeping, stoloniferous at base, 1 — 2f long ; 

 Ivs. hairy on the margin and towards the base, narrow-linear ; sheaths hairy ; 

 spikes 4—5, digitate, spreading, 2 — 3' long, serrated with the uneven spikelets; 

 gluTTKS scabrous on the keel, lanceolate, acute; paUce subequal, the lower 

 broader, enfolding the upper. — % A vigorous creeper, in sands and hard soils, 

 Penn. to Ga. 



48. GYMNOPOGON. Palis. 

 GV. yoiivoi, naked, Trcoycji', beard ; alluding to the long awa of the palea. 



Spikes setaceous, paniculate ; glumes 2, keeled, subequal, the 

 lower with a straight awn from a little below the tip ; rudiment aris- 

 tiform. 



G. RACEMosuM. Palis. (Anthropogon lepturoides. Nutt.) 

 St. ascending, 18 — 24' high, with short internodes ; Ivs. ovate-lanceolate, 

 1 — 2' by 4 — 8", glabrous, flat, .spreading, in 2 rows ; sheaths hairy at the throat; 

 slip, obsolete ; panicle large, pyramidal, branches simple, rigid, verticillate, 

 spreading, 3 — 5' long ; spikelets sessile, appressed ; glumes linear, pungent ; 

 lower palea with an awn at its back 3 — 4 times its length, upper bifid. — % 

 Sandy fields, N. J. to Ga. Aug. 



49. SPARTlNA. 

 Spikelets imbricated in a double row in unilateral, paniculate 

 spikes ; glumes 2, unequal, compressed ; pale.'B 2, subequal, com- 

 pressed, awnless ; style long, bifid. 



1. S. CYNOsuHolDEs. WiUd. (Limnetis. Pers.) 



St. slender, smooth, 3 — 5f high ; Ivs. 2 — 3f long, sublinear, convolute and 

 filiform at the end ; sheatJis striate, glabrous ; panicle loose, slender, composed 

 of 20 or more alternate, one-sided, pedunculate spikes 2 — 3' long ; spikelets 

 arranged on 2 sides of a triangular rachis ; glumes acuminate, one of them 

 with a short awn ; pakiv white and awnless. — % Marshes, Free States and 

 Can. A coarse, sedge-like grass. Aug. 



2. S. JDNCEA. Willd. (Limnetis. Pers.) 



Rt. creeping extensively ; st. erect, rigid, round, smooth, 1 — 2f high ; Ivs. 

 convolute at the edges, spreading, in 2 rows ; spikes 3 — 5 ; ped. smooth ; rachis 

 compressed ; lawer glm/ie 3 times as long as the upper ; palea; obtuse, lower one 

 shorter; sty. 2. — 1\. Marshes and river banks, Free States and Can. Jl., Aug. 



3. S. GLABRA. Muhl. 



St. smooth, succulent, terete, 3 — 5f high; Ivs. concave, erect, about 2f 

 long, J' wide at base, tapering to a long acumination ; spikes 10 — 15, erect and 

 appressed, alternate and sessile upon a triangular rachis; spikelets in a dense, 

 double row. — % Marshes, Indiana ! Aug., Sept. 



50. ATHEROPOGON. Muhl. 



Gr. a^rip, chaff, nbiyoiv, beard; a characteristic term. 



Spikes in a thin, simple raceme ; glumes 2, membranaceous, 2- 

 flowered, lower one setiform ; 5 paleae 2, lower one 3-toothed or 3- 

 bristled, upper bifid ; abortive flower pedicellate, palea3 2 — 3-bristled. 



