Jepson Herbarium
		University of California, Berkeley

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[Annual, shrub] perennial herb, generally aquatic or semiterrestrial, dioecious or monoecious.
Leaf: cauline, opposite, alternate or whorled; submersed blades pinnately divided, segments thread-like; emergent leaves simple, entire to divided.
Inflorescence: raceme, spike, or panicle; flowers 1 or clustered, short-pedicelled to ± sessile.
Flower: generally unisexual, small; calyx tube short, fused to ovary, lobes 2–4; petals generally 2–4; stamens 4 or 8, filaments generally short; ovary inferior, chambers 1–4, styles 2–4, separate, stigmas generally plumose.
Fruit: fleshy or of nut-like mericarps, dehiscent or not.
Seed: generally 1 per chamber.
6–8 genera, ± 100 species: especially s hemisphere, some cultivated. [Aiken & McNeill 1980 J Linn Soc Bot 80:213–222] Haloragis erecta (Murray) Eichler not naturalized in CA. —Scientific Editor: Bruce G. Baldwin.

Plant from rhizomes, occasionally with overwintering buds (late in growing season); occasionally terrestrial.
Stem: simple or branched, generally green.
Leaf: submersed leaves generally whorled, 3–6 per node; emergent leaves entire to pinnately divided, occasionally bract-like.
Inflorescence: generally emergent, spike-like, simple or branched, terminal, flowers in whorls.
Flower: proximal pistillate, middle occasionally bisexual, distal staminate; calyx lobes 4; petals generally 4, ephemeral on staminate flowers, minute or 0 on pistillate flowers; stamens generally 8; ovary 4-chambered.
Fruit: mericarps 4, nut-like.
± 60 species: worldwide. (Greek: many leaves, from leaf segments) [Ceska et al. 1986 Brittonia 38:73–81] Myriophyllum specimens best collected in flower or fruit.
Unabridged note: Plants should be washed first and then "floated" on the herbarium mounting paper in a shallow dish with water [see Ceska & Ceska 1987 Ann Missouri Bot Gard 73:825–827].

Monoecious; winter buds 0.
Stem: > 1 m, dark gray when dry; from strong ± white rhizomes.
Leaf: in whorls of 4–5, 1–2.5 cm, comb-like, with 8–20 thread-like segments; lowermost stem leaves on young shoots bract-like, entire, opposite.
Inflorescence: simple to conspicuously branched spike, 4–8 cm, emergent; bracts 4–10 mm, triangular, minutely serrate.
Flower: stamens 8.
Uncommon. In streams, thermal creeks, shallow water along lakeshores with strong wave action; < 2000 m. High Cascade Range, n High Sierra Nevada, e San Bernardino Mountains;

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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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Bioregions in which taxon occurs	Red area (if present) is the part of the bioregion lying between the upper and lower elevation limits of the taxon; markers link to CCH specimen records. If the markers are obscured, reload the page [or change window size and reload]. Yellow markers indicate records that may have georeferencing or identification issues.
Chart based on elevation range in Manual and elevations and coordinates of CCH records. Data provided by the participants of the Consortium of California Herbaria. Note: About half of the CCH records include both elevation and coordinates.	Map made in collaboration with Scott Loarie. Data provided by the participants of the Consortium of California Herbaria. View all CCH records   CCH collections by month Duplicates counted once; synonyms included. Species do not include records of infraspecific taxa. Blue line denotes Manual flowering time.