Melilotus is a Eurasian leguminous genus of some twenty species. Two species, M. albus and officinalis, introduced to the North American continent are now among the most important broad-leaved forages. M. indicus is a naturalized common weed in the southwestern United States; M. altissimus is locally established in the northeastern states. During the last two decades, the sweet clovers have been under investigation at several stations with respect to the development, through plant breeding, of new and improved strains. Some of the immediate goals have been increased yield, improved forage quality, and freedom from coumarin. In this connection, investigators have felt it desirable to explore the possible reservoir of genetic material available in the related species. Limited populations of many of these species have now been introduced and are being maintained in plant introduction nurseries. The forage characteristics of these plants as well as their interfertility relationships with the cultivated species are the subjects of study in breeding programs at the present time. On several occasions, inquiries have been made to the author with respect to sources of botanical information concerning the species of Melilotus and with regard to keys allowing verification of identifications. The answer: there is apparently no general treatment of the genus nor identification keys in the English language. The most recent keys (in Latin) are provided by Schulz (1901) for the species recognized by him. The objective of the present study has been a survey of the genus, and the treatment of all species in a series of identification keys. For the time being, taxonomic concepts of these species have, with certain specified exceptions, been accepted, "as is." Nomenclature has not been investigated.
Proceedings of the Iowa Academy of Science
©1954 Iowa Academy of Science, Inc.
"Keys to Sweet Clovers (Melilotus),"
Proceedings of the Iowa Academy of Science, 61(1), 119-131.
Available at: https://scholarworks.uni.edu/pias/vol61/iss1/13