376 ENDOGENOUS PLANTS 



Obs. This is not generally diffused, but seems to be restricted 

 to Serpentine banks. The A. flexuosa is so uncertain, as a Chester 

 County plant, that I think it best to omit it, for the present. 



495. TRISE^TUM, Persoon. 

 [Latin; meaning three bristles ; a feature of the lower palea.] 

 Spikelets 2- to several-flowered, usually in a contracted panicle. 

 Lower palea keeled, bicuspidate at apex, and awned below the tip: 

 otherwise nearly as in Air a. Slender perennials, intermediate 

 between Aira and Avena. 



1. T. pal list re, Torrey. Smooth; panicle long and slender, 



somewhat nodding, yellowish-green; spikelets much compressed, 



2- to 3-flowered. 



Avena palustris. MX. $ Fl. Cestr. ed. 2. p. 67. 



MARSH TRISETUM. 



(Mm 2 to 3 feet high; nodes contracted. Leaves 2 to 4 inches long, roughish; 

 tigule oblong, lacerate. Panicle 5 or 6 inches long, often somewhat secund; 

 frrcmc/iesseini-verticillate; spikelets all pedunculate; glumes nearly equal, rather 

 shorter than the florets; upper floret on a hairy pedicel, with the awn of the lower 

 palea contorted, or bent, as long as the floret ; lower floret often awnless,-- the 

 lower palea merely bicuspidate. Grain compressed, free. 

 llab. Swampy meadows : frequent. Fl. June. Fr. July. 



g 2. Lower palea 7- to many-nerved, chartaceous, or subcoriaceous. 



496. DAWTHCraiA, DC. 



[Named after M. Danthoine, a French Botanist.] 



Spikelets 2- to 7-flowered, in a racemose panicle. Glumes nearly 

 equal, awnless, loose, longer than the imbricated florets. Paleae 

 hairy at base, the lower one bifid at apex, with a flattish twisted 

 awn (composed of the 3 middle nerves,) between the segments. 

 Grain smooth and free. 



1. 0. spicata, Beauvois. Leaves short, involute-subulate ; panicle 

 simple, rather secund ; spikelets about 7-flowered. 

 SPICATE DANTHONIA. Wild Oat-grass. 



Perennial. Culms 12 to 18 inches long, slender, somewhat cespitose, often a little 

 decumbent at base. Lower leaves 3 to 6 inches long ; culm leaves short, erect, 

 subulate ; sheaths pilose at throat, and near the nodes ; ligule very short. Panicle 

 short, erect, sometimes the lower branches divided ; spikelets 3 to 5, occasionally 

 10 or 15. Grain oblong, compressed, incurved, longitudinally striate, the apex 

 slightly 2-horned. 

 Hob. Dry banks; borders of woods : common. Fl. June. Fr. July. 



497. AVE'WA, L. 



[The Classical Latin name.] 



Spikelets 2- to 5-flowered, in a loose, large, and somewhat nodding 

 panicle ; florets rather distant, the terminal one abortive. Glumes 

 nearly equal, awnless, loose and membranaceous, often longer than 

 the florets. Lower palea convex, mostly bifid at apex, with a bent 

 or twisted awn on the back (proceeding from the middle nerve, 

 only). Stamens included. Grain oblong, grooved on the upper 

 side, hairy at summit. 



