TREATMENT FROM THE JEPSON MANUAL (1993) |
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©Copyright 1993 by the Regents of the University of California
For up-to-date information about California vascular plants, visit the Jepson eFlora. |
AND IS MAINTAINED FOR ARCHIVAL PURPOSES ONLY |
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 85:531553].
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 135; 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 76:564649; 1985 Sida 11:173188; Wieglet 1988 Feddes Repert 99:249266]
Native |
Perennial from rhizome
Stem generally simple, < 160 cm, subcylindric
Leaves: submersed leaves 1030 cm, < 2 mm wide, linear, blades linear or reduced to petiole; floating leaves 611 cm, < 60 mm wide, oblong to widely elliptic, base slightly lobed, jointed to petiole, tip rounded; stipules 68 cm, free, persistent
Inflorescence: spike, < 5 cm
Fruit 3.55 mm; back rounded, smooth or faintly keeled; sides concave
Chromosomes: 2n=52
Ecology: Shallow, fresh or brackish water, lakes, ponds, bogs, marshes, lagoons, streams
Elevation: < 2700 m.
Bioregional distribution: North Coast, Outer North Coast Ranges, High Cascade Range, High Sierra Nevada, San Joaquin Valley, San Francisco Bay Area, San Bernardino Mountains, Peninsular Ranges, Modoc Plateau
Distribution outside California: to Alaska, e N.America, Baja California, Eurasia
Hybridizes with P. gramineus, P. nodosus.
Horticultural information: water, SUN: 1, 2, 3, 4, 5, 6, 7, 8, 9, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24.