A numerical analysis of major groupings in Medicago employing traditionally used characters

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Abstract
Numerical taxonomic analyses (particularly agglomerative clustering and ordination) were conducted on 55 spp. of Medicago, using 75 mostly vegetative and fruiting characters. The material studied represents all conservatively accepted species of the genus, as well as 14 problematical species of which many are often considered to belong to the genus Trigonella, rather than to Medicago. It was judged appropriate to recognize 12 groupings. These are group 1: M. sativa (alfalfa) and 11 allied species; group 2: M. lupulina and M. secundiflora; group 3: 8 problematical species with respect to whether they should be placed in Medicago or Trigonella; groups 4-8: each made up of a single divergent species, respectively: M. carstiensis, M. radiata, M. orbicularis, M. heyniana and M. arborea; groups 9-12: 4 subgroupings of a larger group of 28 annual species. The composition of the 7 polytypic groups is similar to those of accepted taxa although some realignments of particular species are suggested. Groups 1 and 2 are much more similar to each other than indicated in recent treatments. M. arborea was more dissimilar to all other species examined than thought previously. M. hybrida of group 1 was master link between species traditionally placed in Medicago, and many placed in Trigonella (group 3). The 12 groupings in turn fall into 3 assemblages that are recognized as subgenera or even as genera. These are A: groups 1, 2, 9, 10, 11 and 12; B: groups 3-7, inclusive; and C: M arborea.