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Elodea canadensis
COMMON 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)

Elodea canadensis Michx.
NATIVE
Leaf: generally crowded at stem tips, 3 per node on mid, upper stems; blade generally 5--15 mm, 2--5 mm wide, linear, obtuse or abruptly pointed at tip, flaccid or not. Staminate Inflorescence: bract 8.2--13.5 mm; peduncles, flowers deciduous in late bud or when flowers open. Staminate Flower: sepals 3.5--5 mm, +- 4 mm wide; petals +- 5 mm. Pistillate Flower: sepals +- 2--3 mm. Seed: glabrous. Chromosomes: 2n=24,48.
Ecology: Shallow water, sloughs, ponds, lakes; Elevation: 300--2600 m. Bioregional Distribution: NCoRO, CaRH, SNH, GV, SnFrB, SnGb, SnBr, GB; Distribution Outside California: to British Columbia, eastern United States; naturalized in Europe, Australia. Flowering Time: Jul--Aug
Synonyms: Anacharis canadensis (Michx.) H. St. John; Elodea brandegeeae H. St. John
eFlora Treatment Author: Robert F. Thorne, C. Barre Hellquist & Robert R. Haynes
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Previous taxon: Elodea bifoliata
Next taxon: Elodea nuttallii

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botanical illustration including Elodea canadensis

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Citation for this treatment: Robert F. Thorne, C. Barre Hellquist & Robert R. Haynes 2016. Elodea canadensis, in Jepson Flora Project (eds.) Jepson eFlora, http://ucjeps.berkeley.edu/cgi-bin/get_IJM.pl?tid=24052, accessed on February 11, 2016.

Citation for the whole project: Jepson Flora Project (eds.) 2016. Jepson eFlora, http://ucjeps.berkeley.edu/IJM.html, accessed on February 11, 2016.


Geographic subdivisions for Elodea canadensis:
NCoRO, CaRH, SNH, GV, SnFrB, SnGb, SnBr, GB;
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 provide evidence for eFlora range revision or may have georeferencing or identification issues.
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map of distribution 1
(Note: any qualifiers in the taxon distribution description, such as 'northern', 'southern', 'adjacent' etc., are not reflected in the map above, and in some cases indication of a taxon in a subdivision is based on a single collection or author-verified occurence).

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Data provided by the participants of the Consortium of California Herbaria.
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CCH collections by month

Duplicates counted once; synonyms included.
Species do not include records of infraspecific taxa.
Blue line denotes eFlora flowering time.