Jepson eFlora: Taxon page
Vascular Plants of California
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Elodea bifoliata
TWO-LEAF WATERWEED


Higher Taxonomy
Family: HydrocharitaceaeView DescriptionDichotomous Key
Common Name: WATERWEED FAMILY
Habit: Annual, perennial herb, aquatic, freshwater or marine, glabrous or hairy; monoecious, dioecious, or flowers bisexual. Leaf: basal, alternate, opposite, or whorled, generally sessile, generally +- sheathing at base. Inflorescence: axillary, terminal, or scapose, cyme or flowers 1, subtended by +- sheathing, entire or lobed bract; staminate flowers sometimes deciduous, free-floating. Flower: generally radial; perianth 0 or tube 0 or elongate, peduncle-like in flower; sepals (0)3(4), green; petals (0)3(4), white or not; stamens (0)2--many, generally in 1+ series; ovary inferior, chamber 1 or falsely 6--9, placentas parietal, ovules 1--many, style lobes generally 3, linear, lobed or notched. Fruit: achene or berry-like and dehiscing irregularly, linear to spheric, submersed.
Genera In Family: +- 17 genera, +- 130 species: worldwide; some cultivated for aquaria, others noxious weeds. Note: Ottelia alismoides (L.) Pers. is a possibly extirpated alien.
eFlora Treatment Author: Robert F. Thorne, C. Barre Hellquist & Robert R. Haynes
Scientific Editor: Thomas J. Rosatti.
Genus: ElodeaView DescriptionDichotomous Key


Habit: Perennial herb, rooting at nodes, submersed; dioecious or some flowers bisexual. Stem: slender, generally branched. Leaf: often 2 per node proximally, 3--7 distally, sessile, minutely serrate, midrib abaxially +- smooth. Inflorescence: axillary, sessile or not; flower 1; bract generally notched. Staminate Flower: floating, deciduous or not; perianth tube elongate, slender, peduncle-like; stamens 3--9. Pistillate Flower: floating; perianth tube elongate, slender, peduncle-like; style slender, stigmas 3, lobes 0 or 2. Fruit: cylindric to ovoid. Seed: several, smooth.
Species In Genus: +- 12 species: temperate, tropical America. Etymology: (Greek: of marshes)
Unabridged Reference: St. John, 1965 Rhodora 67:1--35, 155--180
Elodea bifoliata H. St. John
NATIVE
Leaf: generally not crowded at stem tips, 2 per node on lower stems, 2--3 on mid stems; blade generally 4.7--24.8 mm, 0.8--2.5 mm wide, linear to narrowly elliptic, rounded to obtuse at tip, flaccid. Staminate Inflorescence: bract 10--42 mm, proximally slender, distally 6--10 mm, 2.5--5 mm wide, elliptic, inflated, deciduous; peduncles, flowers deciduous soon after flowers open. Staminate Flower: sepals 3.5--5 mm, 2--2.5 mm wide, petals 4.5--5 mm. +- 0.5 mm wide. Pistillate Flower: sepals 1.4--2.8 mm, 1--1.3 mm wide; petals 1.8--4 mm, 1.1--1.3 mm wide. Seed: 2.8--3 mm, ellipsoid, dense-long-hairy.
Ecology: Shallow waters, streams; Elevation: 1300--1800 m. Bioregional Distribution: MP; Distribution Outside California: to British Columbia; western United States to Minnesota. Flowering Time: Jun--Aug
Synonyms: Elodea longivaginata H. St. John; Elodea nevadensis H. St. John
Jepson eFlora Author: Robert F. Thorne, C. Barre Hellquist & Robert R. Haynes
Unabridged Reference: St. John, 1965 Rhodora 67:1--35, 155--180
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Citation for this treatment: Robert F. Thorne, C. Barre Hellquist & Robert R. Haynes 2012, Elodea bifoliata, in Jepson Flora Project (eds.) Jepson eFlora, http://ucjeps.berkeley.edu/eflora/eflora_display.php?tid=24049, accessed on June 16, 2019.

Citation for the whole project: Jepson Flora Project (eds.) 2019, Jepson eFlora, http://ucjeps.berkeley.edu/eflora/, accessed on June 16, 2019.

No expert verified images found for Elodea bifoliata.



Geographic subdivisions for Elodea bifoliata:
MP
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map of distribution 1
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Blue markers indicate specimens that map to one of the expected Jepson geographic subdivisions (see left map). Purple markers indicate specimens collected from a garden, greenhouse, or other non-wild location.
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CCH collections by month

Duplicates counted once; synonyms included.
Species do not include records of infraspecific taxa, if there are more than 1 infraspecific taxon in CA.
Blue line denotes eFlora flowering time.