526 CXXXVIIIL ALISMACEZ:, SAGITTaRIA, 
ponds in N. H. and Mass. Stem long, branched, almost wholly enclosed’ in the 
sheaths. Leaves 2—4’ by 2—3”, very acute, somewhat crowded. 
9. P. paucirtorus. Pursh. (P. gramineum. Michz.) Grassy Pond-weed. 
St. round, dichotomous, filiform ; dvs. linear, alternate, sessile; fis. few in 
a spadix.—A delicate species, in rivers, &c. Leaves numerous, obtuse, tapering 
to the stipulate base, 2—3/ long, a line wide, 1-veined, of a bright green color. 
Peduncle an inch long; terminal, bearing 3—5 greenish fis. above the water, but 
ripening the seeds below. 
10. P. compressus. (P. zosterifolium. Schwm. 
St. compressed, ancipital, flexuous; /vs. broad-linear, obtuse; spike short, 
peduncle elongated.— A very distinct species, in ponds and rivers. Stem 1—2f 
long, branching, weak, flattened, green, with sheathing stipules above the nodes, 
Leaves 3—4/ in length, 2” wide, closely sessile, remote, the margins perfectly 
parallel, ending in an abrupt point. Spadix terminal, 3—1’long, ona peduncle 
—2/ long, and bearing 5—25 flowers. Jl. . 
11. P. pectinATus (and P. marinus. Linn.) Fennel-leaved Pond-weed. 
St. slender, branched, striate, flexuous; dvs. numerous and fascicled in the 
axils, long, narrowly linear, acuminate, on sheathing stipules; spikes cylindrical, 
the lower fils. remote; ped. filiform, long.—Plant submersed in deep water, bushy 
and very leafy, N. Eng.? Middle States! W.to Wis. Lapham! Leaves 4—T7 by 
(less. than) 1”, thin, the midvein scarcely perceptible. Fruit large, purplish, 
rough, a little compressed, neither carinate, nor umbilicate. Jn. 
12. P. pustttus. Linn.? (P. pectinatum. Clark, MS.) Puny Pond-weed. 
St. filiform, flexuous, branched; dvs. linear-subulate, membranaceous, ver 
acute, sessile, not narrower than the stipules; spzkes. capitate, few-flowered; fr, 
ovoid-compressed, umbilicate each. side.—Shallow waters, about Cincinnati, 
Clark! A very. delicate species, wholly submersed, Leaves. 1—2’ by. 3”, a lit- 
tle longer than the internodes. Spikes 3—5-flowered, the peduncles }/ long; 
Fruit with distinct pits, as in P. obrutus, and rather inflated. 
Orver CXXXVIII ALISMACE A—Arismaps. 
Herbs, aquatic. Lvs. parallel-veined. Fs. racemose or paniculate. 
Fis, perfect or mone cious, regular, not on a spadix. } 
Perianth.—Cal. 3-sepaled, green. Cor. 3-petaled, colored (green in the suborder). 
Sta: definite-or indefinite, hypogynous. 
Ova.—Carpels several, 1-celled and 1-seeded, Styles and pt eee several. : 
Fr. dry,.indehiscent. Seeds straight or curved, destitute of albumen.——Genera 5, species 16% 
Conspectus of the Genera. 
peinwer all perfect. Stamens6, .  . « « Alisma, 1 
‘eolored, sepals green, ?Flowers monecious. Stamens indefinite. . .  Sagittaria, 2 
; ee thick, short. Leaves cauline. . . . Zvriglochin. 3 
Petals ( green, like the calyx. ¢ Anthers linear. Leaves all:radical. - «© «+ Steheuchzeria. 4 
1 ALISMA. 
Geltic alis, water; the place it inhabits. 
Flowers © ; stamens 6; ovaries and styles numerous, aggregated, 
becoming in fruit numerous, distinct, compressed achenia.—% caules- 
cent. Lws. radical. Fils. paniculate. 
A. Puantico. (A. parviflora. Ph.) Water Plantain. 
Lvs. oval, abruptly acuminate or cuspidate, subcordate; ach. obtusely 3- 
cornered.—A common, smooth, handsome inhabitant of ponds and ditches. 
Leaves resembling those of the common plantain, 4—6! long, as wide, ending 
in a short, abrupt point, 7—9-veined, entire, on long, radical petioles. Scape 
1—2f high. Branches of the panicle verticillate, with bracts at base. Flowers 
numerous. Petals 3, tinged with pore, roundish, deciduous, larger than the 
green, ovate, persistent sepals. July. 
B. parviflora. Torr. Lws. oval, acuminate, 5—7-veined; fls.small. ~~ 
a SAGIT PART A, 
Lat. sagitta, an-arrow ; from the peculiar form of the leaf. 
Flowers ¢; & with about 24 stamens; 2 with numerous ovaries 
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