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Myriophyllum heterophyllum Michx.

Twoleaf watermilfoil (en), Myriophylle hétérophylle (fr)

Species

Angiosperms > Saxifragales > Haloragaceae > Myriophyllum

Characteristics

Plants hermaphroditic, occasionally monoecious. Stem stout, to 100 cm; internodes crowded. Submerged leaves 4-or 5-whorled or scattered, pectinate, oblong in outline, (1.5-)2-4 × 1-3 cm; segments in 5-12 pairs, filiform, 0.5-1.5 cm. Inflorescence a terminal spike of 4-whorled flowers, 5-35 cm, in monoecious plants lowermost flowers female, uppermost ones male; bracts persistent, eventually reflexed, lanceolate to oblong or obovate, 4-18 × 1-3 mm, margin sharply serrulate; bracteoles ovate, ca. 1.2 × 0.6 mm, margin serrate. Petals 1.5-3 mm. Stamens 4. Fruit 4-loculed, subglobose, 1-1.5 mm; mericarps with 2 finely tuberculate ridges abaxially, apex beaked. Fl. and fr. May-Aug.
More
Stem stout, to 3 mm thick; internodes seldom over 1.5 cm; lvs whorled, (1.5–)2–4 cm, pinnatisect into capillary segments; spikes emersed, 5–15(–40) cm; bracts whorled, persistent and eventually reflexed, lanceolate to oblong or even obovate, sharply serrulate, 4–18 mm (but fairly uniform on each plant); stamens 4; fr subglobose, 1–1.5 mm, each mericarp rounded or more commonly with 2 low keels on the back, scabrous to obscurely tuberculate, with an ascending-recurved beak. N.Y. to w. Ont. and N.D., s. to Fla. and Tex., more abundant southward.
Life form perennial
Growth form herb
Growth support aquatic
Foliage retention deciduous
Sexuality monoecy
Pollination anemogamy
Spread hydrochory
Mature width (meter) -
Mature height (meter) 0.5 - 1.0
Root system -
Rooting depth (meter) -
Root diameter (meter) -
Flower color
Blooming months
JanFebMar
AprMayJun
JulAugSep
OctNovDec
Fruit color -
Fruiting months
JanFebMar
AprMayJun
JulAugSep
OctNovDec
Nitrogen fixer -
Photosynthetic pathway c3

Environment

Light 7-9
Soil humidity 10-12
Soil texture 1-2
Soil acidity -
Soil nutriment -
Hardiness (USDA) 5-8

Usage

Uses environmental use
Edible -
Therapeutic use -
Human toxicity -
Animal toxicity -

Cultivation

Can be grown by cuttings.
Mode cuttings
Germination duration (days) -
Germination temperacture (C°) -
Germination luminosity -
Germination treatment -
Minimum temperature (C°) -23
Optimum temperature (C°) -
Size -
Vigor -
Productivity -

Images

Myriophyllum heterophyllum unspecified picture

Distribution

Myriophyllum heterophyllum world distribution map, present in Austria, Canada, China, Cuba, Germany, Spain, France, United Kingdom of Great Britain and Northern Ireland, Guatemala, Croatia, Mexico, and United States of America

Conservation status

Myriophyllum heterophyllum threat status: Least Concern

Identifiers

LSID urn:lsid:ipni.org:names:430415-1
WFO ID wfo-0000373526
COL ID 458ZB
BDTFX ID 43398
INPN ID 109144
Wikipedia (EN) Link
Wikipedia (FR) Link

Synonyms

Myriophyllum mexicanum Myriophyllum heterophyllum
WorldFloraDB 2024