- Myriophyllum heterophyllum is a perennial, aquatic herb that has leaves of two noticeably different forms.
- The submerged leaves are finely dissected, whorled, reddish/greenish-brown, and 0.5-2.5 in. (1.3-6.4 cm) long. The emergent leaves are small, oval, bright green, whorled and up to 0.25 in. (0.6 cm) wide. Emergent leaves stand 6-8 in. (15.2-20.3 cm) out of the water and may not be apparent until late summer.
- Flowering occurs from June to September. Flowers are emergent on 2-12 in. (5.1-30.5 cm), green to reddish stalks. Petals are less than 0.1 in. (3 mm) in length and are subtended by downward curved bracts.
- Fruits are small, nearly round and have a rough surface.
- Ecological Threat
- Myriophyllum heterophyllum is native to the southern United States, but is considered invasive in much of the northeast. This species is listed as endangered or threatened in three states (Kentucky, Ohio, and Pennsylvania).
- Invasive Plant Atlas of New England - University of Connecticut
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EDDMapS Distribution - This map is incomplete and is based only on current site and county level reports made by experts, herbaria, and literature. For more information, visit www.eddmaps.org
State Invasive List - This map identifies those states that list this species on their invasive species list. For more information, visit Invasive.org
Invasive Listing Sources
|Common Name Reference:|| USDA, NRCS. 2010. The PLANTS Database. National Plant Data Center, Baton Rouge, LA, USA.|
|Scientific Name Reference:||USDA, NRCS. 2010. The PLANTS Database. National Plant Data Center, Baton Rouge, LA, USA.|