Contains 5 accepted taxa overall.
Characteristics
Classification
Citation
MYRIOPHYLLUM Linnaeus, Sp. Pl. 992. 1753.
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TYPE: Myriophyllum spicatum Linnaeus Lectotypified by Britton & A. Brown, Ill. Fl. N. U.S., ed. 2. 2: 614. 1913.
Species
| Scientific Name | Common Name | Status | Photos |
|---|---|---|---|
| Myriophyllum aquaticum | PARROT FEATHER WATERMILFOIL | Not Native OBL (NWPL) | |
| Myriophyllum heterophyllum | TWOLEAF WATERMILFOIL | Native OBL (NWPL) | |
| Myriophyllum laxum | LOOSE WATERMILFOIL | Native OBL (NWPL) | |
| Myriophyllum pinnatum | CUTLEAF WATERMILFOIL | Native OBL (NWPL) | |
| Myriophyllum spicatum | EURASIAN WATERMILFOIL; SPIKE WATERMILFOIL | Not Native OBL (NWPL) Y |
[Family identification key]
1. Plants dioecious (only pistillate in North America); leafy stems mostly emersed; petiole 5-7 mm long; all leaves pectinate; emersed leaves mostly 2.5-3.5 cm long
1. Plants monoecious, lower flowers pistillate, upper staminate; leafy stems mostly submersed; petiole <2 mm long; submersed leaves pectinate; emersed leaves pinnately divided, serrate, or bract-like, <2 cm long
2
2. Leaves gray-green to dark green, strictly whorled, typically retaining their shape upon drying; stamens 8
2. Leaves green to reddish green, pseudowhorled to alternate (may appear whorled), typically collapsing and entangled upon drying; stamens 4
3
3. Leaf division typically 12-28 per leaf; distal flowers whorled; fruit prominently beaked
3. Leaf divisions typically 8-16 per leaf; distal flowers alternate; fruit short-beaked
4
4. Bracts 1-3 mm long, shorter than most inflorescence internodes, pectinate to entire; fruit surface smooth to papillose
4. Bracts 4-10 mm long, subequal to longer than inflorescence internodes, pinnatifid to pectinate; fruit surface tuberculate