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Key to families | Table of families and genera
This text currently parallels The Jepson Manual: Vascular Plants of California, Second Edition that is now available at the University of California Press.
Text appearing in blue on this page will not appear in the printed book; it will be displayed only on the Web. 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.
Annual [per], in water or on wet ground; monoecious [ dioecious].
Stem: slender, generally ascending under water, floating on surface, or prostrate on ground, generally much-branched.
Leaf: generally opposite, 4-ranked, lance- linear to spoon-shaped, entire [lobed].
Inflorescence: flowers 1–2(4) per leaf axil, bracts 2, ± white, generally inflated, or 0.
Flower: minute, unisexual; perianth 0.
Staminate flower: stamen 1, filament elongate.
Pistillate flower: ovary superior, slightly lobed at tip and base, chambers 4, styles 2, thread-like.
Fruit: 0.6–1.6[2.4] mm, ± dry, ± grooved lengthwise, splitting into 4 achene-like units.
± 75 species: tropics, temperate. (Greek: beautiful hair, from long linear submerged leaves of some of Medit taxa) [Lansdown 2009 Novon 19:364–369] Taxonomically difficult; mature fruit and 10× magnification needed for identification. Callitriche peploides Nutt. a nursery weed in s CA; Callitriche stenocarpa Hegelm., misappl. to various CA taxa, but recorded from many sites in the Rocky Mtns and could be expected in CA.
Unabridged references: [Fassett 1951 Rhodora 53:137–155, 161–182, 185–194, 209–222; Philbrick & Jansen 1991 Syst Bot 16:478–491; Philbrick & Les 2000 Aq Bot 68:123–141]
1. Lf dark green, contrasting strongly with pale stem; leaves all ± linear or tapering from near base; no leaves with > 1 central vein ..... C. fassettii
1' Lf pale green and not contrasting strongly with stem; leaves ± linear and vein 1, to broad, petioled, and veins > 1
2. Fr wing 0 or winged only distal to middle
3. Fr length >= width, wing distal to middle only or 0; fruit with evident lines of cells on faces ..... C. palustris
3' Fr length ± = width, generally wing 0; cells on fruit faces obscure ..... C. heterophylla
4. Fr 0.8–1.4 mm ..... var. bolanderi
4' Fr 0.6–0.8 mm ..... var. heterophylla
2' Fr winged from tip to base
5. Peduncle in fruit 2–25 mm
6. Fr length >= width, 1–1.2 mm, 0.9–1.2 mm wide ..... C. longipedunculata
6' Fr length < width, 0.7–1 mm, 1.1–1.4 mm wide ..... C. marginata (2)
5' Peduncle in fruit 0–1 mm
7. Mature fruit gray-brown, not contrasting strongly with wing ..... C. stagnalis
7' Mature fruit dark brown to black, contrasting strongly with translucent wing
8. Fr length < width, 0.7–1 mm, 1.1–1.4 mm wide ..... C. marginata (2)
8' Fr length = width, 1–1.5 mm, 1–1.5 mm wide ..... C. trochlearis
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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