616 CLXI. GRAMINEA, UnioLa. 
spikelets terete, linear, purplish, about 5-flowered; fs. obtuse, indistinctly. 5- 
veined,—2 Salt marshes, Ms., Bigelow. June. 
18. P. aquatica. £8. Americana, Torr. (P. aquatica, Ph.) 
Smooth; st. stout, leafy, 4—5f high; dvs. 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.—2. Wet mea- 
dows, Free States and Can, A very large, handsome poa. Aug. 
19. P. pentira. Torr. 
Smooth ; st. erect, round, 3f high; dvs. 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; lower 
palea 5-veined, 5-toothed at the apex when old.—2| Swamps, Mass., N. H,! to 
Penn. Notvery common. June, July. 
20. P. rascicuLata. Torr. 
Very smooth; st. firm and leafy, oblique, round, branched at base, 1—2f 
high ; lvs. flat, lance-linear ; panicle spreading, branches fasciculate, crowded, 
straight; spikelets oblong, somewhat racemed, sessile, crowded, about 3-flow- 
ered; glumes minute, unequal.—2 Salt marshes, N. Y. 
21. P. pecrinacea. Michx. (P. pilosa. Muhl. P. tenella. Ph.) 
St. ceespitose, oblique, geniculate at base, 8—12’ high; ws. 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 palea persistent on the rachis which thus 
is made finally to appear pectinate.-—@ In sandy fields, Mid, and S. States. 
July, Aug. 
22, P. REPTANS. 
3 2; st. branched, creeping, rooting at the joints, 6—12’ long; dws. 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. Eracrostis. (P. obtusa. Nutt. Briza eragrostis. Muil.) 
St. oblique or decumbent, geniculate, 1—2f long; Jws. 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 [il.! It has a 
strong, peculiar odor. Aug. § 
42. BRIZA. ; 
Gr. Bp12, to nod, or hang down; alluding to the pendulous spikelets. 
Spikelets cordate-ovate, 6—9-flowered ; glumes 2, shorter than the 
lower flowers ; paleze ventricose, lower one cordate at base, embracing 
the upper which is suborbicular and much shorter; caryopsis beaked. 
B. MEDIA. 
St. naked above, 1—2f high; dvs. 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; pale@ veinless.—2Natu- 
ralized in the vicinity of Boston, Bigelow. May. 
43, UNIOLA. 
Lat. wnus, 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 palez boat-shaped at 
the end, truncate and mucronate between the lobes, upper subulate, 
somewhat bifid; scales emarginate; caryopsis with 2 horns. 
1, U. vatirouia. Michx. Broad-leaved Uniola. 
St. 2—4f high, smooth, subsimple; lvs. 8—18’ by 6—12”, lance-linear, 
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