dwarf waterclover
(Marsilea minuta)
This species is Introduced in the United States
ORIGIN: Africa, Asia, Australia, Europe
GROWTH TRAITS: Waterclovers consist of a group of very similar and closely related plants. They are aquatic perennial ferns that are anchored in the sediment by slender, branching rhizomes that root at nodes and internodes. Leaves (fronds) arise from rhizomes on slender petioles typically 2-7" (5-18 cm) long, but up to 12" (30 cm) long if the plant is rooted deeply. Leaves may be floating or slightly emerged; emerged leaves may sometimes close at night and reopen with daylight. Each leaf resembles a 4-leaf clover with 4 wedge-shaped leaflets. Each leaflet is 0.25-1" (0.6-2.5 cm) long and wide, typically smooth above, and may have a few short hairs on the underside. Spore-producing structures (sporocarps) are attached to short, branched stalks up to 0.5" (12 mm) long arising from the bases of leaf petioles. Sporocarps are brown, hairy when young, oval-shaped, and 0.2" (5 mm) long by 0.12" (3 mm) wide. In cold climates, plants often die back to their roots in winter; they may grow year-round at warm locations.
REPRODUCTION: Though sporocarps can be found near the base of leaf petioles, they may remain dormant for decades. The majority of reproduction in the USA is vegetative through rhizomes.
HABITAT: Waterclovers grow best in shallow, slow-moving waters in semi-shade to full sun in sandy or loamy soils. They can infrequently be found growing terrestrially on muddy ground.
LOOK-ALIKES: Native waterclovers are very similar and are currently the source of much taxonomic confusion. The native hairy waterclover (Marsilea vestita) is perhaps the easiest to differentiate with its hairy foliage and unbranched sporocarp stalks. Expert help is likely required for help identifying other Marsilea spp.
CITATIONS:
Rawlins, K.A., R.L. Winston, C.T. Bargeron, D.J. Moorhead, and R. Carroll. 2018. New Invaders of the Southeast. USDA Forest Service, Forest Health Assessment and Applied Sciences Team, Morgantown, West Virginia. FHTET-2017-05. Retrieved from http://bugwoodcloud.org/resource/pdf/FHTET-2017-05_New%20Invaders_SE.pdf
GROWTH TRAITS: Waterclovers consist of a group of very similar and closely related plants. They are aquatic perennial ferns that are anchored in the sediment by slender, branching rhizomes that root at nodes and internodes. Leaves (fronds) arise from rhizomes on slender petioles typically 2-7" (5-18 cm) long, but up to 12" (30 cm) long if the plant is rooted deeply. Leaves may be floating or slightly emerged; emerged leaves may sometimes close at night and reopen with daylight. Each leaf resembles a 4-leaf clover with 4 wedge-shaped leaflets. Each leaflet is 0.25-1" (0.6-2.5 cm) long and wide, typically smooth above, and may have a few short hairs on the underside. Spore-producing structures (sporocarps) are attached to short, branched stalks up to 0.5" (12 mm) long arising from the bases of leaf petioles. Sporocarps are brown, hairy when young, oval-shaped, and 0.2" (5 mm) long by 0.12" (3 mm) wide. In cold climates, plants often die back to their roots in winter; they may grow year-round at warm locations.
REPRODUCTION: Though sporocarps can be found near the base of leaf petioles, they may remain dormant for decades. The majority of reproduction in the USA is vegetative through rhizomes.
HABITAT: Waterclovers grow best in shallow, slow-moving waters in semi-shade to full sun in sandy or loamy soils. They can infrequently be found growing terrestrially on muddy ground.
LOOK-ALIKES: Native waterclovers are very similar and are currently the source of much taxonomic confusion. The native hairy waterclover (Marsilea vestita) is perhaps the easiest to differentiate with its hairy foliage and unbranched sporocarp stalks. Expert help is likely required for help identifying other Marsilea spp.
CITATIONS:
Rawlins, K.A., R.L. Winston, C.T. Bargeron, D.J. Moorhead, and R. Carroll. 2018. New Invaders of the Southeast. USDA Forest Service, Forest Health Assessment and Applied Sciences Team, Morgantown, West Virginia. FHTET-2017-05. Retrieved from http://bugwoodcloud.org/resource/pdf/FHTET-2017-05_New%20Invaders_SE.pdf
Maps
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 Lists - This map identifies those states that have this species on their invasive species list or law.
Invasive Listing Sources
Taxonomic Rank
| Domain: Eukarya |
| Kingdom: Plantae |
| Division: Pteridophyta |
| Class: Filicopsida |
| Order: Hydropteridales |
| Family: Marsileaceae |
| Genus: Marsilea |
| Marsilea minuta |
References
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.