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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.
Plants generally submerged except inflorescence, or vegetative when all-submerged (emergent to ± terrestrial); rhizomes, stolons slender. Stem: unbranched proximal to inflorescence. Leaf: blade flat to convex, 3-sided, or abaxially keeled. Inflorescence: heads axillary and terminal, 2–60+; bracts leaf-like, distal reduced. Staminate flower: stamens 2–8. Pistillate flower: ovary chambers 1–2(4), stigmas generally 1(2–4). Fruit: drupe-like, spongy; perianth parts attached, style and generally stigmas persistent as beak; floating, water-dispersed.
± 17 species: northern temperate, western Pacific. (Probably Greek: swaddling band, for strap-shaped leaves) [Kaul 2000 FNANM 22:271–277] Fruit head diam including fruit beaks; fruit body lengths except beak, stalk-like base; beak lengths including stigmas.
Unabridged references: [Cook & Nicholls 1986 Bot Helv 96:213–267, 1987 Bot Helv 97:1–44]
1. Inflorescence main axis branches (0)1–4; staminate heads ± 10–60; stigmas > 1 on 5–100% of pistillate flowers; fruit body (except beak) ± truncate to hemispheric distally; plants ± terrestrial or emergent, not aquatic, erect ..... S. eurycarpum
2. Stigmas 2(3–4) on ± (40)60–100% of pistillate flowers; fruit body except beak 8–9 mm, 5–7 mm wide, distally ± truncate to low-rounded ..... var. eurycarpum
2' Stigmas 2 on ± 5–40% of pistillate flowers; fruit body except beak 5–8 mm, 3–6 mm wide, distally rounded to generally tapered ..... var. greenei
1' Inflorescence main axis branches 0; staminate heads <= 10; stigma 1; fruit body (except beak) distally tapered or rounded; plants terrestrial to aquatic, erect to limp
3. Staminate heads 1–2; stigma 0.3–0.8 mm; fruit beak 0.5–1.5 mm; plants generally aquatic, limp ..... S. natans
3' Staminate heads 3–7; stigma (0.6)0.8–2(2.5) mm; fruit beak >= 1.5 mm; plants terrestrial to emergent, aquatic, limp or not
4. Leaf blades ± flat, or convex, or generally some obscurely 3-angled or keeled, widest 1–5 mm wide; fruit beak 1.5–2.2 mm; staminate heads 3–4(5), crowded in flower; plants generally aquatic, limp, distal parts floating ..... S. angustifolium
4' Leaf blades generally 3-angled or keeled, especially proximally, generally obscure in pressed specimens, widest 5–13 mm wide; fruit beak (2)3–4(5) mm; staminate heads 3–7, well-separated to crowded in flower; plants generally terrestrial to emergent, erect, or aquatic and limp with distal parts floating ..... S. emersum
Citation for the whole project: Jepson Flora Project (eds.) [year] Jepson eFlora, http://ucjeps.berkeley.edu/IJM.html [accessed on month, day, year]
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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