Name: |
- Elodea, from the Greek, `eleios
(heleios), "of the marsh or meadow"
- canadensis, from the Latin, "of Canada"
- Common name from its aquatic habitat and general distribution
- Other common names include: American Elodea, Anacharis, Canadian
Pondweed, Ditch Moss, Water Thyme, Élodée du Canada (Qué),
Vandpest (Dan), Kanada vesikatk, vesihain (Est),
Vesirutto, Kanadanvesirutto (Fin), Kanadische Wasserpest
(Ger), Brede Waterpest (NL), Vasspest (Nor), Vodomor
Kanadský (Slovak), Vattenpest, Vanlig Vattenpest (Swe)
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Taxonomy: |
- Kingdom Plantae, the Plants
- Division Magnoliophyta, the Angiosperms (flowering plants)
- Class Liliopsida, the Monocotyledons
- Subclass Alismatidae
- Order Hydrocharitales
- Family Hydrocharitaceae, the Frog's-bit Family
- Genus Elodea, the Water Weeds
- Taxonomic Serial Number: 38937
- Also known as Anacharis canadensis, Anacharis canadensis
var. planchonii, Elodea brandegae, Elodea ioensis,
Elodea linearis, Elodea planchonii, Helodea canadensis,
Philotria canadensis, Philotria linearis
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Description: |
- A submerged perennial herb
- Leaves bright green, typically in whorls of 3 or occasionally
4 (some opposite), spreading to recurved, linear, flat, entire, and
2 to 5 times as long as wide. Whorls compact near growth tip, with spacing
between whorls gradually increasing further down the stem. Upper and
middle leaves linear-lanceolate (on male plants) or oblong-lanceolate
to ovate-lanceolate (on female plants), 3/8"-5/8" long, 1-5
mm wide, mostly more than 1.5 mm wide, round tip, more strongly overlapping
on female plants. Lower leaves opposite, reduced, ovate-lanceolate.
- Stem slender, round in cross section, branching, 8"-40"
long. Winter buds appear as short, compact branches in late summer.
- Roots white, unbranched, and thread-like. Not always present.
- Flowers imperfect; male and female borne on different
plants.
- Male Flower borne in upper leaf axils, at end of a threadlike,
¾"-12" long stalk, reaching to the surface. Spathes
cylindric, about ½" long, inflated up to 3/16" wide.
- Sepals green, elliptic, about 1/8"-3/16" long
- Petals white, clawed, linear, about 3/16" long
- Stamens 9, the inner 3 raised on a common stalk
- Female Flower borne in upper leaf axils, at end of a threadlike,
¾"-12" long stalk, reaching to the surface. Spathes
elongated, cylindric, ¼"-½" long.
- Sepals 3, green, oblong-elliptic, about 1/8"
long
- Petals 3, white, oblanceolate, about 1/8" long
- Stigmas 3, 2-cleft, on syles about 3/16" long
- Fruit an ovoid capsule, about ¼" long containing
several seeds. Ripens underwater.
- Seed fusiform, glabrous, narrowly cylindrical, about 3/16"
long
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Identification: |
- A submerged aquatic plant, identifiable as a Waterweed by its
short, blunt leaves borne in whorls.
- Similar to the less common Western Waterweed (Elodea
nuttallii) but larger and more robust in such minor detail as:
- male flower spathes 5/16" or more (vs 3/16" or less);
at the end of threadlike stalks (vs stalkless breaking off to become
free floating).
- styles usually 4mm (vs 2 mm or less)
- leaves usually more than 1.7 mm wide (1mm-5mm, averaging 2mm vs.
1.7mm or less)
- seeds 4.5mm-5.5mm or more (vs 3.5mm-4.5mm)
- When in flower:
- a plant with fully formed, utterly stalkless flowers is a male
nuttallii
- plants having flowers on threadlike stalks over 4"
long are male or female canadensis
- a plant having fully formed flowers raised on threadlike stalks
which are all less than 4" long is probably a
female nuttallii.
- When flowers are not present, it's something of a judgement call based
upon the somewhat smaller, more delicate structure, and paler green
leaves of nuttallii.. There is no shame in simply identifying
a plant as Elodea.
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Distribution: |
- Nova Scotia to British Columbia, south to North Carolina, Alabama,
Arkansas, Oklahoma, Colorado, and California.
- Introduced in Europe, Asia, Australia.
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Habitat: |
- Quiet waters of marshes, lakes, and streams, to depths of 25' or more.
Also the Great Lakes.
- Typically found in calcareous, "hard" water.
- Often forms large masses.
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Associates: |
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History: |
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Uses: |
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Reproduction: |
- By Seed
- Flowers June-August
- Male flowers rise on long stalks and split open, spreading pollen
onto the water's surface where it drifts and may, by chance, reach
a female flower. Pollination occurs at the water's surface at the
whim of wind and wave.
- Rarely successful
- Vegetatively
- By fragmentation of the stem.
- Most common means of reproduction
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Propagation: |
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Cultivation: |
- Hardy to USDA Zone 3 (average minimum annual temperature -40ºF)
- Useful as oxygenator in garden ponds, and as shelter for small fishes
and aquatic invertebrates.
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Links: |
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Comments: |
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Last updated on
26 February, 2004
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