Jepson Flora Project: Jepson Interchange    

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Jepson Interchange (more information)
©Copyright 1993 by the Regents of the University of California

  • Up-to-date information about California vascular plants is available from the Jepson eFlora.



Perennial from long rhizomes, colonial, glabrous, generally aquatic (submersed to emergent), monoecious
Stem erect and stiff or submersed and floating above, cylindric, solid
Leaves basal and cauline, alternate, ± 2-ranked, spongy or stiff; sheath open; blade linear, flat, keeled, or triangular in X -section, spongy
Inflorescence spike-like (cylindric, dense) or head-like (spheric), terminal or axillary; staminate above pistillate, generally on same axis; flowers subtended by 1, minute bract
Staminate flower: perianth parts 0 or 1–6 and scale-like; stamens 1–8
Pistillate flower: perianth parts 0 or 1–6 and flattened; ovary 1, chambers 1–2(3), ovules 1–2(3)
Fruit: achene; wall thin, splitting in water
Genera in family: 2 genera, ± 25 species: worldwide. Sparganium formerly treated in Sparganiaceae. Family description and key to genera by R.F. Thorne.



Robert F. Thorne

Perennial from slender or corm-like rhizomes, glabrous, aquatic (submersed or emergent)
Stem slender, cylindric, solid; upper part erect or floating
Leaf: blade long, flat, keeled, or triangular, sometimes floating, spongy
Inflorescence head-like, spheric, axillary and terminal, sessile or short-peduncled; bracts leaf-like, gradually reduced upward; flowers sessile, each generally subtended by 1 bractlet
Staminate flower: perianth parts 1–6, scale-like; stamens 1–8, filaments free or fused at base
Pistillate flower: perianth parts 1–6, oblanceolate to spoon-like, greenish, persistent in fruit; ovary superior, chambers 1–2(3), ovule 1 per chamber, styles 1 or deeply 2(3)-lobed
Fruit fusiform to obconic, sessile or stalked; top tapered, truncate, or dome-like, beaked or not
Species in genus: 14 species: n temp, se Asia, sw Pacific
Etymology: (Greek: swaddling band, from long, narrow leaves)
Reference: [Cook & Nicholls 1986–7, Bot Helv 96:213–267;97:1–44]


S. natans L.


Plant generally submersed
Stem 0.8–4 dm, floating above, flexible, simple
Leaf 0.6–4(6) dm, 1.5–6(10) mm wide, generally flat
Staminate inflorescence generally 1
Pistillate inflorescences 1–3, well separated, 7–10 mm diam in fruit
Fruit 2–4 mm, 1–2.5 mm wide, widely elliptic to obovoid-fusiform, slightly narrowed at middle or not, greenish or brownish, sessile or short-stalked
Chromosomes: 2n=30
Ecology: Lakes, ponds
Elevation: 2000–2500 m.
Bioregional distribution: High Cascade Range, n&c High Sierra Nevada, Modoc Plateau
Distribution outside California: to Alaska, e N.America; circumboreal
Synonyms: S. minimum Fr
See the CNPS Inventory for information about endangerment and rarity.
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