616 CLXI. GRAMINE^E. UNIOLA. 



spikelets terete, linear, purplish, about 5-flowered ; fls. obtuse, indistinctly 5- 

 veined. 9| Salt marshes, Ms., Bigelow. June. 



18. P. AQUATICA. 0. Americana. Torr. (P. aquatica. Ph.) 



Smooth ; st. stout, leafy, 4 5f high ; Ivs. broad-linear, flat, thin ; panicle 

 erect, diffuse, branches at length spreading, flexuous, 3 5 together, in half 

 whorls ; spikelets linear, purple, with 6 8 ovate-obtuse flowers. 1\. Wet mea- 

 dows, Free States and Can. A very large, handsome poa. Aug. 



19. P. DENTATA. Torr. 



Smooth ; st. erect, round, 3f high ; Ivs. flat, linear, 10 16' long, glaucous 

 beneath ; stip. elongated ; panicle large, loose, few-flowered, branches capillary, 

 spreading ; spikelets lanceolate, about 5-flowered ; lower glume 3- veined ; lowc* 

 palea 5-veined, 5-toothed at the apex when old. 1J. Swamps, Mass., N. H. ! t 

 Penn. Not very common. June, July. 



20. P. FASCICULATA. Torr. 



Very smooth ; st. firm and leafy, oblique, round, branched at base, 1 2r 

 high ; Ivs. flat, lance-linear ; panicle spreading, branches fasciculate, crowded, 

 straight ; spikelets oblong, somewhat racemed, sessile, crowded, about 3-flow- 

 ered; glumes minute, unequal. 7J. Salt marshes, N. Y. 



21. P. PECTINACEA. Michx. (P. pilosa. Mutt. P. tenella. Ph.) 



St. caespitose, oblique, geniculate at base, 8 12' high ; Ivs. flat, smooth, 

 pilose at base, 5-veined, 2 4' long ; sheaths bearded at the throat ; panicle large, 

 loose, capillary, purplish, hairy in the axils, branches subverticillate ; spikelets 

 linear, with 5 9 acute flowers ; upper patea persistent on the rachis which thus 

 is made finally to appear pectinate. (D In sandy fields, Mid. and S. States. 

 July, Aug. 



22. P. REPTANS. 



J 1 9; st. branched, creeping, rooting at the joints, 6 12' long; Ivs. subu- 

 late, flat, 2 3' long ; sheaths open, pilose on the margin and throat ; panicle 

 1 2' long, branches short, simple, in fascicles, few-flowered ; spikelets linear- 

 lanceolate, with 12 20 acuminate flowers. Swamps, N. Y. to Ky. ! Jl., Aug. 



23. P. ERAGROSTIS. (P. obtusa. Nutl. Briza eragrostis. Muhl.) 



St. oblique or decumbent, geniculate, 1 2f long; Ivs. lanceolate, attenu- 

 ate at end, scabrous on the margin and above ; sheaths pilose at the throat ; stip. 

 short, bearded ; panicle expanding, branches subdivided, flexuous, subpilose in 

 the axils ; spikelets ovate-oblong, 12 20-flowered ; glumes nearly equal. A 

 beautiful grass, introduced into fields and roadsides, N. Eng. to 111. ! It has a 

 strong, peculiar odor. Aug. ft 



42. BRIZA. 



Gr. /?j3t^o), to nod, or hang down ; alluding to the pendulous spikelets. 



Spikelets cordate-ovate. 6 9-flowered ; glumes 2, shorter than the 

 lower flowers ; palese ventrieose, lower one cordate at base, embracing 

 the upper which is suborbicular and much shorter ; caryopsis beaked. 



B. MEDIA. 



St. naked above, 1 2f high; Ivs. flat, smooth, lance-linear; stip. short 

 obtuse ; panicle erect, few-flowered, branches wide-spreading, capillary, pur- 

 plish, bearing the ovate or cordate, tumid, pendant and tremulous spikelets at 

 the ends, these are about 7-flowered, greenish-purple ; palea veinless. ^Natu- 

 ralized in the vicinity of Boston, Bigelow. May. 



43. UNIOLA. 



Lat. unus, one ; on account of the aggregation of many flowers into one spikelet. 



Spikelets compressed, 3 20-flowered; lower flower abortive, 

 glumes 2, shorter than the lower flower ; lower palea3 boat-shaped at 

 the end, truncate and mucronate between the lobes, upper subulate, 

 somewhat bifid ; scales emarginate ; caryopsis with 2 horns. 



1. U. LATIFOLIA. Michx. Broad-leaved Uniola. 



St. 2 4f high, smooth, subsimple ; Ivs. 818' by 6 12", lance-linear, 



