0RAMINEJE. 439 



flower abortive, with a single, membranaceous palea ; upper 

 flower perfect, with 2 cartilaginous, subequal paleae ; car} op- 

 sis striate. — Root annual. 



1. D. sanguina'lis. Purple Finger Grass. Crab Grass. 



Stems decumbent at base, radiating and branchincp at the lower joints, 1 — 2 

 feet long; Zeaws linear-lanceolate, on long, loose sheaths, softly pilose, the 

 sheaths strigosely hairy ; spikes 3 — 5 inches long, fasciculate at the top of the 

 stem, 5 — 9 together ; spikdets in pairs, oblong-lanceolate, closely appressedto 

 the rachis,in2 rows. Common in cultivated grounds. Aug. — Oct. Ann. 



2. D. GLABRA. 



Stem generally decumbent, rarely rooting at the joints, a foot long ; leaves 

 short, flat, nearly glabrous ; spikes digitate, spreading, 3—4 ; spikdets crowd- 

 ed, ovoid ; glume equaling the abortive flower, both hairy. Sandy fields. 

 Aug. Sept. 



3. D. filifo'rmis. 



Stem erect, filiform, simple, 12 — 18 inches high; leaves short, nearly 

 smooth, narrow-lanceolate; spikes 2 — 4, filiform, erect ; spikehts in 3s, all 

 pedicellate ; glume solitary, as long as the abortive flower. Dry, gravely 

 soils. Aug. 



20. SETA'RIA. 

 Inflorescence a compound, cylindrical spike; spikelets 

 2-flovvered, invested with an involucre of 2 or more bristles; 

 glumes, flowers, paleoeand fruit as in the genus Panicum. 



1. S. vi'ridis. Wild Timothy. 



Stem smooth, 2 — 3 feet high ; leaves lanceolate, flat, minutely serrulate ; 

 sheaths striate, hairy on the margin, and witli a setose stipule ; spike cylin- 

 dric, compound, terminal, green ; involucre of 4 — 10 fasciculate bristles, much 

 longer than the spikelets ; palea: nf the perfect fioiver longitudinally striate, 

 punctate. Common in cultivated grounds. July. Aug. 



2. S. GLAL'CA. Bottle Grass. 



Stem 2 — 3 feet high; lenvcs lanceolate, carinate, rough, hairy at base; 

 sheaths striate, smooth; stipule setose ; spike cylindric, yellowish green, 2 — 4 

 inches long ; involucre of G — 10 fascicled, scabrous bristles much longer than 

 the spikelels ; palece of the perfect jiower transversely rugose. Fields and road- 

 sides. July. Aug. 

 S. S. vkrticilla'ta. 



Stem smooth, about 2 feet high ; leaves lanceolate, rough-edged ; sheaths 

 smootii, hairv on the margin; spicate panicle composed of short, divided 

 branches in interrupted verticels, 2 — 3 inches long ; bristles of the involucre 

 in pairs, rough backwards ; palece of the perfect flower roughish punctate. 

 Sandy fields. July. 



4. S. Ita'lica. 



Stem somewhat compressed, about 4 feet high ; leaves lanceolate, 1 — 2 feet 

 long, an inch wide ; sheaths roughish, pilose at the throat; spike compound, 

 interrupted at the base, nodding, C — 8 inches long; spikelets conglomerate ; 

 involucre of 2 bristles, several times longer than the flower. Ditches. July. 



Tribe 5. PHALARIDE^. 



liifloreutnce a contracted panicle. Spikelets solitary, with 1 perfect flower and 1 — 2 imperfect 

 ones. Lower palea awned or mucronate, upper with 2 keels. 



21. PHA'LARIS. 

 Spikelets 1-flowered ; glumes 2, subequal, carinate ; paleae 

 2, coriaceous, awnless, shorter than the glumes, coating the 



