Lycopus rubellus

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Lycopus rubellus
Lycopus rubellus SEF.jpg
Photo by the Southeastern Flora Database
Scientific classification
Kingdom: Plantae
Division: Magnoliophyta - Flowering plants
Class: Magnoliopsida - Dicots
Order: Lamiales
Family: Lamiaceae
Genus: Lycopus
Species: L. rubellus
Binomial name
Lycopus rubellus
Natural range of Lycopus rubellus from USDA NRCS Plants Database.

Common Names: stalked bugleweed;[1] taperleaf water horehound[2]

Taxonomic Notes

Synonym: L. velutinusRydberg; L. angustifolius[2]


Lycopus rubellus is a dioecious perennial forb/herb.[2] It produces white flowers.[3] Leaves are lance-ovate and 5-12 cm long with a sessile or short petiole. Rhizomes produce tubers at the extremities.[4]


This species occurs from Maine, westward to Michigan, and southward to Florida and Texas.[1] Reports also exist for its occurrence in Oregon.[2]



L. rubellus is found in marshes, swamp forests, and bottomlands.[1] On Arkansas floating mats, L. rubellus composed less than 1% of the vegetative cover.[5] In Indiana, L. rubellus grows on floating logs, stumps, and at bases of living trees. It is also a characteristic species of sinkhole wetlands.[6] In Mississippi, it is found in bottomland hardwoods, swamps, and margins of ponds.[7]


In the southeastern and mid-Atlantic United States, L. rubellus flowers from June through November.[1] For L. rubellus in Mississippi, flowering occurs from September through October.[7]

Seed bank and germination

After submerging seeds in a water filled jar for 130 days, speeds from L. rubellus still germinated and produced seedlings.[8] However, in South Carolina, L. rubellus is only found above or at the waterline.[9]


The polar axis of L. rubellus pollen grains have been reported as 23.75-30.00 µm[10] and 12.0-16.8 µm.[11] This large difference between studies could be caused by geographic variation or differences in chromosome number.[10]

Conservation and Management

Cultivation and restoration

Photo Gallery

References and notes

  1. 1.0 1.1 1.2 1.3 Weakley AS (2015) Flora of the Southern and Mid-Atlantic States. Chapel Hill, NC: University of North Carolina Herbarium.
  2. 2.0 2.1 2.2 2.3 USDA NRCS (2016) The PLANTS Database (, 01 February 2018). National Plant Data Team, Greensboro, NC 27401-4901 USA.
  3. Plant database: Lycopus rubellus. (01 February 2018) Lady Bird Johnson Wildflower Center. URL:
  4. Tobe JD, Burks KC, Cantrell RW, Garland MA, Sweeley ME, Hall DW, Wallace P, Anglin G, Nelson G, Cooper JR, Bickner D, Gillbert K, Aymond N, Greenwood K, Raymond (1998) Florida Wetland Plants: An Identification Manual. Florida Department of Environmental Protection, Tallhassee, FL.
  5. Huffman RT, Lonard RI (1983) Successional patterns on floating vegetation mats in a southwestern Arkansas bald cypress swamp. Castanea 48(2):73-78.
  6. Homoya MA, Hedge CL (1982) The upland sinkhole swamps and ponds of Harrison County, Indiana. Proceedings of the Indiana Academy of Science 92:383-388.
  7. 7.0 7.1 Jones SB Jr. (1976) Mississippi flora V. the mint family. Castanea 41(1):41-58.
  8. Shull GH (1914) The longevity of submerged seeds. The Plant World 17(11):329-337.
  9. Collins B, Wein G (1995) Seed bank and vegetation of a constructed reservoir. Wetlands 15(4):374-385.
  10. 10.0 10.1 Moon H, Hong S (2003) Pollen morphology of the genus Lycopus (Lamiaceae). Annales Botanici Fennici 40:191-198.
  11. Trudel MCG, Morton JK (1992) Pollen morphology and taxonomy in North American Labiatae. Canadian Journal of Botany 70(5):975-995.