* 
448 ALISMACEX. (WATER-PLANTAIN FAMILY.) 
short. Achenium I-seeded, 2-3-keeled on the back. — Roots fibrous. Leaves 
mostly oval or cordate, nerved, shorter than the scape. Flowers white. 
1. A. Plantago, L. Leaves long-petioled, ovate or oblong, acute, rounded 
or cordate at the base, 3~9-nerved ; panicle large, lax, the whorled branches and 
elongated filiform pedicels bracted at the base; achenia obtuse, 15-20 in a 
whorl. (A. trivialis, and A. parviflora, Pursh.) — Ditches and margins of ponds 
in the upper districts, Georgia, and northward. July and Aug. — Leaves 2! - 4 
long. Panicle 1°-2° long. 
3. ECHINODORUS, Richard. 
Flowers perfect, mostly in whorled racemes. Sepals 3. Petals 3, imbricated 
in the bud, withering. Stamens few or numerous. Ovaries few or many, im- 
bricated, forming ribbed achenia in fruit, usually beaked with the persistent 
style. — Herbs, with petioled nerved leaves. Heads mostly bur-like. 
1. E. parvulus, Engelm. Small; leaves lanceolate or spatulate, mostly 
acute, finely nerved and somewhat pinnately-veined, commonly shorter than the 
single or clustered 1 — 6-flowered scapes ; flowers mostly clustered or umbelled, 
on long bracted pedicels which are recurved in fruit, stamens 9; achenia few, 
shorter than the ovate sepals, obovate, flattened at the sides, and surrounded 
with 5 prominent ribs, beakless. — Margins of shallow ponds, Middle Florida, 
and westward. July and Aug. — Scapes 1'—4' high. Achenia black and 
shining. 
2. E. rostratus, Engelm. Leaves varying from lanceolate to ovate, acute 
at each end, or rounded or cordate at the base, 5-nerved, about as long 8$ the 
petiole ; scape rigid, erect, longer than the leaves; whorls few; pedicels erect or 
spreading ; sepals ovate, many-nerved, shorter than the oval bur-like head ; sta- 
mens 12; style longer than the ovary; achenia numerous, strongly 3-ribbed on 
the back, with fainter lateral and intermediate ribs, beaked with the long persist 
ent style. — South Florida, and westward. — Scape simple, 3' — 8 high, or ae 
casionally 2° high and paniculately branched. Leaves 1/-2! long. Flowers 
wide. 
3. E. radicans, Engelm. Leaves large, long-petioled, ovate, cordate x 
truncate at the base, obtuse, 7-9-ribbed ; scape elongated, prostrate, rooting 7 
proliferous; whorls several, remote; pedicels slender, spreading, Or ™ ai 
stamens about 20; style shorter than the ovary ; heads globose, longer than 
many-nerved sepals ; achenia very numerous, short-beaked, ribbed and pod 
denticulate on the back. (Alisma radicans, Nutt.) — Swamps, Florida pen 
Carolina, and westward. July ~ Sept. — Scape 2°-4° long. Leaves y z 
Flowers 8” ~ 12" wide. 
«4 ~SAGITTARIA, L. Arrow-cRass- ks 
Flowers monocious, in a whorled raceme, the upper ones sterile. a 
Petals 3, imbricated in the bud, withering. Stamens few 0T ® 
