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Key to families | Table of families and genera

Specimen numbers are hyperlinked to records in the Consortium of California Herbaria data view where possible. Taxa are hyperlinked to entries in the Jepson Interchange via the "[Online Interchange]" link.

 

POTAMOGETONACEAE PONDWEED FAMILY

C. Barre Hellquist, Robert F. Thorne & Robert R. Haynes


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.
3 genera, ± 95 species: worldwide. [Haynes & Hellquist 2000 FNANM 22:47–74] Recently treated elsewhere to include Zannichelliaceae. Ruppia moved to Ruppiaceae. —Scientific Editor: Thomas J. Rosatti.
Unabridged references: [Angiosperm Phylogeny Group 1998 Ann Missouri Bot Gard 85:531–553]

Key to Potamogetonaceae

1. Stipules of submersed leaves free from blade base or fused to it < 1/2 stipule length; leaves submersed, also floating or not; peduncle stiff; inflorescence generally floating to emergent ..... POTAMOGETON

1' Stipules of submersed leaves fused to blade base >= 2/3 stipule length; leaves submersed; peduncle flexible; inflorescence submersed ..... STUCKENIA

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Citation for an individual treatment: [Author of taxon treatment] [year]. [Taxon name] in Jepson Flora Project (eds.) Jepson eFlora, [URL for treatment]. Accessed on [month, day, year].
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