Murdannia keisak - aneilema, marsh dewflower
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Low growing
herbaceous plant found along shallow freshwater wetlands including
marshes, swamps, ponds, streams, rivers, ditches, and canals. It can
grow in heavily shaded to sunny environments. Aneilima is a serious
ecological threat because it is capable of forming solid mats of
vegetation that exclude native plants. Herbicide applied post-emergence
is the most effective control method available. This procedure may need
to be repeated for several years. Mechanical control should be
restricted, because aneilima reproduces vegetatively. Recreational use
in the area should be restricted to prevent the spread. Because it
occurs in wetlands, the number of herbicides available for controlling
aneilima is limited. Coupled with the fact that few other viable
control methods are available, prevention may be the most important
means of managing aneilima.
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| Marsh dewflower infestation |
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| Marsh dewflower leaves |
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Click image for larger version
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Marsh Dewflower
Murdannia keisak
Family: Commelinaceae (USDA 2007)
Other Names: wartremoving herb, Aneilema keisak Hassk., marsh dew flower, Asian spiderwort, aneilema (USDA 2007), Aneilema oliganthum Franch. & Sav., marsh dewflower (USF 2007)
USDA Code: MUKE
Legal Status: No Federal status. Listed as a noxious weed in the state of Washington. (USDA 2007)
Identification
Growth form: A succulent annual that is usually immersed and grows along stream banks, swamps, and along the edges of ponds and lakes. Found primarily in the piedmont and coastal plain regions of the southeastern United States. (VTU 2007)Flower: The flowers occur at the ends of the stems or arise from the position between the stems and leaves (leaf axils). Flowers can occur singly or in clusters of 2 to 4. All flowers occur on short flower stalks (pedicels) and consist of 3 pink to purple petals that are approximately 1/3 inch long. (VTU 2007)
Seeds/Fruit: A capsule that is approximately 1/3 inch long. (VTU 2007)
Leaves: Alternately arranged, lanceolate in outline, up to 3 inches long and 5 mm wide. The bases of the leaves clasp and surround the stems. (VTU 2007)Stems: Succulent, rooting at the nodes. Stems grow prostrate along the ground and eventually ascend to approximately 18 inches in height. (VTU 2007)
Identifying Characteristics: Immersed aquatic plants that usually grow along the edges of ponds, lakes, or in marshes. Additionally, the stems that root at the nodes, lanceolate leaves, and flowers with 3 pink to purple flowers are all characteristics that help in the identification of marsh dayflower. (VTU 2007)Marsh dewflower (wartremoving herb) is an annual, emergent plant that invades wetlands throughout the southeastern and pacific northwestern United States. Plant stems are succulent, form roots at the nodes, and grow prostrate along the ground. Leaves are alternate, lance-shaped, and up to 3 inches long. Small, pink, 3 petaled flowers occur singly or in small clusters and are located terminally and in the leaf axils. Marsh dewflower invades water edges and marshes often growing immersed. It forms dense mats that out-compete native vegetation. Marsh dewflower is native to eastern Asia. It was accidentally introduced into the United States in South Carolina around 1935. (Invasive.org, 2007)Marsh dewflower, a member of the spiderwort family and native of eastern Asia, was first noted in 1935 in cultivated rice paddies in South Carolina. It escaped and has become established in the wild in 18 southern states and the District of Columbia. Marsh dewflower prefers damp soil at the edge of freshwater tidal marshes, around ponds and along slow moving streams. Its aggressive growth enables it to out-compete native plants by forming dense mats. Seeds are dispersed by wildlife. It also spreads when floods distribute root fragments to new locations. (Swearingen et.al., 2002)Similar species
Exotics:
Natives: Native alternatives include water plantain (Alisma subcordatum), three-way sedge (Dulichium arundinaceum), duck-potato or arrowhead (Sagittaria latifolia or rigida). (Swearingen et. al., 2002)
Impacts
Agricultural: A common weed in rice patties from which it was most likely introduced.
Ecological:
Human:
Habitat and Distribution
General requirements: M. keisak prefers damp soil at the edge of freshwater tidal marshes, around ponds and along slow moving streams. Its aggressive growth enables it to out-compete native plants by forming dense mats. (Swearingen et. al., 2002)
Distribution: Invades wetlands throughout the southeastern and pacific northwestern United States. (Invasive.org, 2007) Historical: Its native range includes China, Japan, Korea, Nepal, Cambodia, Laos, and Vietnam. (USDA 2007). M. keisak was most likely introduced to the United States accidentally with rice cultivation. (Dunn and Sharitz 1990)
Biology/Ecology
Life cycle:
Mode of reproduction: M. keisak can reproduce by seed and vegetatively.
Seed production:
Seed bank:
Dispersal: Seeds are dispersed by wildlife. It also spreads when floods distribute root fragments to new locations. (Swearingen et.al., 2002)
Hybridization:
Control
Biocontrol:
Mechanical: Hand pulling may be effective if done before the plant sets seed. (Swearingen et. al., 2002)
Fire:
Herbicides: Glyphosate treatments were ineffective when applied early in the season. (Swearingen et. al., 2002)Cultural/Preventative:
Note of Caution:
Integrated Management Summary
References Dunn, C.P and Sharitz, R.R. June 1990. The History of Murdannia keisak (Commelinaceae) in the Southeastern United States. Castanea. 55(2): 122-129.Invasive.org. 2007. Marsh Dewflower. http://www.invasive.org/browse/subject.cfm?sub=3053 .Swearingen, J., K. Reshetiloff, B. Slattery, and S. Zwicker. 2002. Plant Invaders of Mid-Atlantic Natural Areas. National Park Service and U.S. Fish & Wildlife Service, 82 pp., http://www.invasive.org/eastern/midatlantic/muke.html .University of South Florida (USF). 2007. Atlas of Florida Vascular Plants - Murdannia keisak. http://www.plantatlas.usf.edu/main.asp?plantID=205 .University of Washington Herbarium (UWH). 2007. Murdannia keisak – wart-removing-herb. http://biology.burke.washington.edu/herbarium/imagecollection.php?
Genus=Murdannia&Species=keisak .
USDA, NRCS. 2007. The PLANTS database (http://plants.usda.gov/plants). National Plant Data Center, Baton Rouge, LA 70874-4490 USA.Virginia Tech University (VTU). 2007. Marsh Dayflower, Asian Dayflower, or Asian Spiderwort. http://www.ppws.vt.edu/scott/weed_id/aneke.htm .
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