Melilotus, known as Melilot or Sweet-clover, is a genus in the family Fabaceae. Members are known as common grassland plants and as weeds of cultivated ground. Originally from Europe and Asia, it is now found worldwide.
This legume is commonly named for its sweet smell, which is due to its high content of the perfume agent coumarin. This chemical is responsible for the sweet smell of hay and is bitter to the taste, probably produced by the plant to discourage ingestion by animals. Coumarin, in turn, is converted by fungi (including Penicillium, Aspergillus, Fusarium, and Mucor) into a poisonous anticoagulant, called dicoumarol, that may be found in moldly or spoiled sweet-clover. This compound was the historical cause of so-called sweet-clover disease, recognized in cattle since the 1920s.
Melilotus is often used as a green manure and turned into the soil to increase its nitrogen and organic matter content. It is especially valuable in heavy soils because of its deep rooting. However, it may fail if the soil is too acidic. It should be turned into the soil when 8 to 10 inches tall. Unscarified seed is best sown in spring when the ground is not too dry; scarified seed is better sown in late fall or even in the snow, so it will germinate before competing weeds the following spring.
Blue melilot (Trigonella caerulea) is not a member of the genus, despite the name.
The genus Melilotus currently has nineteen recognized species:
- Melilotus albus Medik.
- Melilotus altissimus Thuill.
- Melilotus dentatus (Waldst. & Kit.) Pers.
- Melilotus elegans Salzm. ex Ser.
- Melilotus hirsutus Lipsky
- Melilotus indicus (L.) All.
- Melilotus infestus Guss.
- Melilotus italicus (L.) Lam.
- Melilotus macrocarpus Coss. & Durieu
- Melilotus officinalis (L.) Lam.
- Melilotus polonicus (L.) Desr.
- Melilotus segetalis (Brot.) Ser.
- Melilotus siculus (Turra) B. D. Jacks.
- Melilotus speciosus Durieu
- Melilotus spicatus (Sm.) Breistr.
- Melilotus suaveolens Ledeb.
- Melilotus sulcatus Desf.
- Melilotus tauricus (M. Bieb.) Ser.
- Melilotus wolgicus Poir.
- Woodgate, Katherine; Maxted, Nigel; Bennett, Sarita Jane (1996). "Genetic resources of Mediterranean pasture and forage legumes". In Bennett, Sarita Jane; Cocks, Philip Stanley. Genetic resources of Mediterranean pasture and forage legumes. Current Plant Science and Biotechnology in Agriculture 33. Norwell, MA: Kluwer Academic Publishers. p. 203. ISBN 0-7923-5522-9.
- "Phytochemicals.info:Coumarin". Retrieved 2011-11-26.
- Edwards WC, Burrows GE, Tyr RJ: 1984, Toxic plants of Oklahoma:clovers. Okla Vet Med Assoc 36:30-32.
- Behzad Yamini, Robert H. Poppenga, W. Emmett Braselton, Jr., and Lawrence J. Judge (1995). "Dicoumarol (moldy sweet clover) toxicosis in a group of Holstein calves". J Vet Diagn Invest 7:420-422.
- Five Acres and Independence by M.G. Kains. 1973.
- "Species Nomenclature in GRIN". Retrieved 2010-08-04.