Evidence for the hybrid origin of Lathyrus plitmannii (Leguminosae)

ABSTRACT

The hypothesis that Lathyrus plitmannii may be of hybrid origin was tested on a morphological data set, derived from measurements of 50 herbarium specimens, by employing the computer program HYWIN. Results showed that all the specimens of L. plitmannii were putative hybrids and that the highest ranked pair of specimens that best matches the morphologies of its parents was L. gorgonei and L. pseudocicera. Examination of the distribution patterns of the three species shows that L. plitmannii is confined to regions common to both putative parents and that hybrids could be formed, assuming that genetic barriers were overcome. Additional supporting evidence includes overlaps in the edaphic requirements and the habitats of the three species. Lathyrus plitmannii is recognised as a distinct species that should be regarded as derivative of hybridisation between L. gorgonei and L. pseudocicera.

KEY WORDS:

• Fabaceae
• hybrid
• HYWIN
• Lathyrus
• Leguminosae
• morphology