Jepson Flora Project: Jepson Interchange    

 
link to manual TREATMENT FROM THE JEPSON MANUAL (1993) previous taxon | next taxon
Jepson Interchange (more information)
©Copyright 1993 by the Regents of the University of California

    THIS PAGE IS NO LONGER UPDATED
    AND IS MAINTAINED FOR ARCHIVAL PURPOSES ONLY
  • Up-to-date information about California vascular plants is available from the Jepson eFlora.

POTAMOGETONACEAE

PONDWEED FAMILY

Robert F. Thorne

Annual, perennial herb, aquatic, (generally fresh to alkaline water), glabrous, from rhizomes or small, bulb-like, winter buds
Stems erect, simple to branched, cylindric or flattened
Leaves simple, cauline, alternate or in subopposite pairs; submersed thread-like to round, sessile or petioled; floating, if present, elliptic to ovate, petioled, leathery; sheath open, continuous with petiole or ± free from leaf base, generally with stipules, stipules sometimes fused, ligule-like
Inflorescence: spike or head-like, axillary or terminal, generally emergent, peduncled; bracts 0
Flower bisexual; perianth parts 0 or 4, clawed; stamens 2 or 4, if 4, each fused to base of perianth part, sessile or filament short, wide, anthers open to outside; pistils 4, ovary 1-chambered, ovule 1, style short or stigmas sessile
Fruit: drupe
Seed 1
Genera in family: 3 genera, ± 95 species: worldwide
Recent taxonomic note: Recently treated to include Zannichelliaceae [Angiosperm Phylogeny Group 1998 Ann Missouri Bot Gard 85:531–553].

POTAMOGETON

PONDWEED

Annual, perennial herb, from rhizomes or small, bulb-like, winter buds
Stem simple or branched, cylindric or flattened, rooting at lower nodes
Leaves simple, cauline, generally alternate, generally flat, generally green, margin generally entire; submersed leaves sessile or petioled, linear to round, tip rounded to acuminate, veins 1–35; floating leaves, if any, elliptic to ovate, generally petioled, leathery; stipules free or fused, sheath-like below leaf junction, free or fused (ligule-like) above leaf junction
Inflorescence: cylindric spike or head-like, axillary or terminal, floating to emergent
Flower: inconspicuous; perianth parts 4, clawed, greenish; stamens 4, attached to base of perianth, anthers generally sessile; ovule attached at chamber base, style short or stigma sessile
Fruit generally obovate, sessile, floating
Species in genus: ± 90 species: mostly temp n hemisphere
Etymology: (Greek: river neighbor, from aquatic habitat)
Reference: [Haynes 1974 Rhodora 76:564–649; 1985 Sida 11:173–188; Wieglet 1988 Feddes Repert 99:249–266]

Native

P. illinoensis Morong

SHINING PONDWEED

Perennial from rhizomes
Stem generally much-branched, < 150 cm, slender, cylindric
Leaves: submersed leaves sessile or petioles < 2 cm, blade 6–20 cm, 15–50 mm wide, elliptic to oblanceolate, margin finely serrate near tip, tip acute to short-pointed; floating leaves, if any, with blades 4–12 cm, 2–6 cm wide, widely elliptic to oblong-elliptic, generally > petiole; stipules 2.5–7 cm, free, persistent
Inflorescence: spike, generally < 6 cm
Fruit ± 4 mm; back keeled; beak slightly below tip
Chromosomes: n=52
Ecology: Lakes, ponds, streams
Elevation: 400–2350 m.
Bioregional distribution: North Coast Ranges, Cascade Range, High Sierra Nevada, San Joaquin Valley, Central Coast, San Francisco Bay Area, Outer South Coast Ranges, San Gabriel Mountains, San Bernardino Mountains, Peninsular Ranges, Great Basin Floristic Province
Distribution outside California: to British Columbia, e Canada, Texas, Baja California; also C.America and Caribbean
Flowering time: Jun–Aug
Hybridizes with P. gramineus, P. nodosus, P. richardsonii.
Horticultural information: TRY.

previous taxon | next taxon
bioregional map for POTAMOGETON%20illinoensis being generated
 


Retrieve Jepson Interchange Index to Plant Names entry for Potamogeton illinoensis
Retrieve dichotomous key for Potamogeton
Overlay Consortium of California Herbaria specimen data by county on this map
Show other taxa with the same California distribution | Read about bioregions | Get lists of plants in a bioregion
Return to the Jepson Interchange main page
Return to treatment index page
Glossary


University & Jepson Herbaria Home Page |
General Information | University Herbarium | Jepson Herbarium |
Visiting the Herbaria | On-line Resources | Research |
Education | Related Sites
Copyright © by the Regents of the University of California