Marsilea minuta, or dwarf waterclover is a species of aquatic fern in the Marsileaceae family. Not to be confused with Marsilea minuta E.Fourn. 1880, which is a synonym for Marsilea vestita. Other common names include gelid waterklawer, small water clover, airy pepperwort, and pepperwort, though the lattermost also applies to plants in the genus Lepidium. In French it is called marsilea à quatre feuilles (literally "four-leafed marsilea") and petite marsilée (literally "little Marsilea"), the latter appearing to be a calque with the Latin botanical name. In Chinese it is 南国田字草 (nan guo tian zi cao), literally "southern field word grass," referencing the similarity of the leaflet shape to the Chinese character for "field." The Koch Rajbongshi people and Garo people call it shusni shak. It is called 'শুশনি শাক' ('shushni shak') in Bengali. In parts of India it can be called sunisanakka In Indonesian it is semanggi (literally "clover"), but this name also applies to Marsilea crenata. In Japanese it is nangokudenjiso and in Thai it is phakwaen. In Malaysian it is tapak itek (literally "site duck"). In the Philippines it is kaya-kayapuan (literally "so crowded").
M. minuta has a strongly variable appearance, which often leads to confusion with closely related species. In the water the plant is creeping and spreading, while on land it can appear cushion-like. It typically is perennial but sometimes appears annual. It is a tenagophyte, with the juvenile growing submerged and the adult typically terrestrial.
It has a light brown to green rhizome that is 0.4-0.8mm thick with short tan hairs at the ends and internodal roots. The land leaves are on erect, terete, 5–13 cm long petioles. The leaflets are 0.8-1.7 cm by 1.2–2 cm, mostly glabrous, cuneate or flabellate. The leaves in water are typically not floating, but emergent from the water. Fertile leaves are produced on land with up to four sporocarps each at penduncles near the base of the petiole. It has a small sporocarp that is 2.6-4.1mm long, 2.4-3.1mm wide, and 1.3-1.7mm thick. The sporocarp has a superior tooth at the apex of the stalk and an inferior tooth at the base. The sporocarp has a conspicuous 1.5-2.2mm long raphe, about ⅔ the length of the sporocarp and semi-terete. Unlike a few Marsilea species, M. minuta sporocarps mature above ground.
|Number of chromosomes||40|
M. minuta is thought to be closely related to Marsilea quadrifolia. Molecular phylogenetic analysis of the genus Marsilea puts both in a widespread Old World subgroup also called "Marsilea" along with M. angustifolia, M. drummondii, M. crenata, and M. fadeniana and indicating that M. crenata is actually a synonym of M. minuta.
Habitat and ecology
Marsilea minuta can grow from sea level up to 1,950m in elevation in ponds and other shallow water. It can grow in fresh water or brackish water in clay or sandy soil. The plant can develop into large colonies, and can be weedy. Some of its preferred habitat is being lost to agriculture but as it readily grows in Paddy fields, drainage ditches, and other marginal areas its overall population is stable. It has the potential to be invasive and dispersal through aquarium trade and other human means should be limited.
- Central African Republic
- Democratic Republic of the Congo
- Côte d'Ivoire
- South Africa
- South Sudan
- Sri Lanka
- Trinidad and Tobago
The leaves and sporocarps of M. minuta are eaten by many waterfowl species, and the intact sporocarps pass through undigested to be spread to new areas. Elophila responsalis also feeds on the leaves, but is not thought to do much damage to the plant.
The plant is susceptible to herbicides such as bensulfuron-methyl. cinosulfuron, 2,4-Dichlorophenoxyacetic acid, oxyfluorfen, and paraquat. Otherwise it can tolerate high levels of organic pollution.
The plant is used traditionally in China for edema, skin injuries, snakebite, and inflammation. In Mymensingh District it is traditionally used to treat cough, headache, hypertension, sleep disorders, and respiratory diseases. It is combined with Nardostachys jatamansi and after development by Asima Chatterjee sold as an ayurvedic treatment for epilepsy called "Ayush-56." However, Ayush-56 does not show encouraging results in treating the disease. It is also used as a phytoremediator of arsenic while growing with rice plants. 
- Beentje, H.J. (2017). "Marsilea minuta (Dwarf Water Clover, Gelid Waterklawer, Small Water Clover)". The IUCN Red List of Threatened Species. doi:10.2305/IUCN.UK.2017-1.RLTS.T164326A84291386.en. Retrieved 24 August 2017.
- "Marsilea minuta L. — The Plant List". The Plant List. 2012. Retrieved 23 August 2017.
- Marsilea minuta L. in GBIF Secretariat (2016). GBIF Backbone Taxonomy. Checklist Dataset https://doi.org/10.15468/39omei https://www.gbif.org/species/5274876 accessed via GBIF.org on 2017-09-20.
- Cook, Christopher D. K. (28 March 1996). "Cyperaceae". Aquatic and Wetland Plants of India: a reference book and identification manual for the vascular plants found in permanent or seasonal fresh water in the subcontinent of India south of the Himalayas. New York, NY: Oxford University Press. p. 105. ISBN 9780198548218. OCLC 32968513.
- Marsilea minuta L. in GBIF Secretariat (2016). GBIF Backbone Taxonomy. Checklist Dataset https://doi.org/10.15468/39omei accessed via GBIF.org on 2017-09-17
- Johnson, David M. (25 June 1986). Systematics of the New World Species of Marsilea (Marsileaceae). Systematic Botany Monographs. 11. Ann Arbor, MI: The American Society of Plant Taxonomists. pp. 39–40, 51, 63. doi:10.2307/25027626. ISBN 978-0912861111. ISSN 0737-8211. JSTOR 25027626. OCLC 13455360.
- "Marsilea minuta (pepperwort)". Invasive Species Compendium. Wallingford, UK: CAB International. 15 May 2008. Retrieved 29 August 2017.
- Lin, Y. X.; Johnson, D. M. (6 June 2013). Wu, Z. Y.; Raven, P. H.; Hong, D. Y., eds. "Marsileaceae" (PDF). Flora of China. 2–3: 123–124. Retrieved 25 August 2017.
- Sarker, Sujan Kumer; Hossain, A.B.M. Enayet (June 2009). "Pteridophytes of Greater Mymensingh District of Bangladesh used as Vegetables and Medicines" (PDF). Bangladesh Journal of Plant Taxonomy. 16 (1): 54. doi:10.3329/bjpt.v16i1.2746. ISSN 2224-7297. Retrieved 25 August 2017.
- Krishnamoorthy, Ennapadam S.; Shorvon, Simon; Schachter, Steven; Misra, Vivek, eds. (6 April 2017). "34 Ayurveda and Yoga in the Management of Epilepsy". Epilepsy: A Global Approach (PDF)
|url=(help). Cambridge University Press. p. 160. doi:10.1017/9781139547918. ISBN 9781108232159. Retrieved 29 August 2017.
- Schelpe, E. A. C. L. E. (1970). "eFloras Results For Marsilea minuta". Flora Zambesiaca. Royal Botanic Gardens, Kew. Retrieved 29 August 2017.
- Nagalingum, Nathalie S.; Schneider, Harald; Pryer, Kathleen M. (2007). "Molecular Phylogenetic Relationships and Morphological Evolution in the Heterosporous Fern Genus Marsilea". Systematic Botany. 32 (1): 16–25. doi:10.1600/036364407780360256. ISSN 1548-2324.
- Srivastava, R. B. (1985). "Ferns of the Indo-Nepal border" (PDF). Proceedings of the Royal Society of Edinburgh, Section B: Biological Sciences. 86: 471. doi:10.1017/S0269727000008770. ISSN 0269-7270. OCLC 5549574398. Retrieved 16 January 2018.
23. M. minuta L. 40 20 2.9-4.6 Diploid
- Terra, G.J.A. (1966). "IIID Ferns and Related Plants". Tropical vegetables: vegetable growing in the tropics and subtropics especially of indigenous vegetables. Communication. 54e (1st ed.). Amsterdam: Koninklijk Instituut voor de Tropen. p. 57. OCLC 9027279.
Marsilea minuta L. (Marsileaceae) I Ce (3.3%)
- Basak, Swati (May 2015). "Women, Science, Education And Empowerment: Asima Chatterjee, The Genius Lady" (PDF). IMPACT: International Journal of Research in Humanities, Arts and Literature. 3 (5): 133–138.
- Tripathi, M; Maheshwari, MC; Jain, S; Padma, MV (2000). "Ayurvedic Medicine and Epilepsy" (PDF). Neurology Journal of Southeast Asia. 5: 1–4. Retrieved 29 August 2017.
- Hassi, Ummehani; Hossain, Md. Tawhid; Huq, S. M. Imamul (2017-10-10). "Mitigating arsenic contamination in rice plants with an aquatic fern, Marsilea minuta". Environmental Monitoring and Assessment. 189 (11): 550. doi:10.1007/s10661-017-6270-2. ISSN 0167-6369. PMID 29018967.
- Hassi, U; Hossain, MT; Huq, SMI (2018-07-08). "Nitrogen, phosphorus and potassium status of rice co-planted with a novel phytoremediator, Marsilea minuta L.". Bangladesh Journal of Agricultural Research. 43 (2): 211–218. doi:10.3329/bjar.v43i2.37326. ISSN 2408-8293.