Common Name: PONDWEED FAMILY
Habit: Annual, perennial herb, aquatic, (generally fresh to alkaline), glabrous, from rhizomes, tubers, or winter buds. Stem: erect, simple to branched, cylindric to compressed, rooting at lower nodes; nodal glands present or not. Leaf: simple, cauline, alternate or in subopposite pairs; submersed thread-like to round, sessile or petioled; floating present or not, elliptic to ovate, petioled, leathery; sheath open, continuous with petiole or +- free from blade base, generally stipuled, stipules fused and ligule-like or not. Inflorescence: spike, cylindric to spheric, axillary or terminal, generally emergent, peduncled; bracts 0. Flower: inconspicuous, bisexual; perianth parts [0]4, clawed, +- green, limb generally adaxially concave; stamens [2]4, each fused to base of perianth part [or not], filament generally 0 [short, wide], anthers open to outside; pistils [1]4, ovary 1-chambered, ovule 1, attached to chamber base, style 0 or short. Fruit: drupe, generally obovate, sessile. Seed: 1.
Genera In Family: 3 genera, +- 95 species: worldwide. Note: Recently treated elsewhere to include Zannichelliaceae. Ruppia moved to Ruppiaceae.
eFlora Treatment Author: C. Barre Hellquist, Robert F. Thorne & Robert R. Haynes
Scientific Editor: Thomas J. Rosatti.

Common Name: PONDWEED
Habit: Perennial herb, rhizomed, tubered or not, winter buds 0. Stem: branched, cylindric. Leaf: submersed, sessile, channeled, entire, tip acute to abruptly pointed, notched, or rounded, veins 1--5; stipules fused to leaf blade >= 2/3 stipule length. Inflorescence: submersed; peduncle flexible. Fruit: beaked or not, keel 0. Chromosomes: x=13.

Unabridged Reference: Börner 1912 Botanisch-systematische Notizen. Abh. Naturwiss. Vereine Bremen 21:245--282; Holub 1977 Preslia 69:361--366