Genetic Resources and Crop Evolution

, Volume 65, Issue 6, pp 1571–1580 | Cite as

Are Melilotus albus and M. officinalis conspecific?

  • Stephen Darbyshire
  • Ernest Small
Research Article


The principal economic species of the genus Melilotus are white sweet-clover (Melilotus albus) and the extremely similar yellow sweet-clover (M. officinalis). Although they are widely recognized as distinct species, some influential references in North America reduce the former to a subspecific rank or even merely a conspecific synonym of the latter. Given their importance and the large numbers of germplasm collections, the doubt needs to be resolved. This review of relevant published evidence finds that in addition to the difference in floral colour, the traditional segregation of the two as distinct species is best supported by very strong reproductive barriers as well as divergent DNA sequences in three barcoding genes. Additional but weaker confirmation of separateness is provided by studies reporting differences in external morphology, biochemistry, seed protein profiles, karyotype and DNA microsatellites.


Melilotus albus Melilotus officinalis Trigonella alba Trigonella officinalis Sweet-clover Melilot Conspecific Species definition 



We thank J. Hsiung for preparing the drawings in Fig. 2 and S. Mechanda for assistance in preparing the manuscript. Two anonymous reviewers provided useful comments on the manuscript.

Compliance with ethical standards

Conflict of interest

The authors declare that they have no conflict of interest.


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Copyright information

© Crown 2018

Authors and Affiliations

  1. 1.Agriculture and Agri-Food Canada, Science and Technology BranchOttawa Research and Development CentreOttawaCanada

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