The Biological Species of the Genus Lens L.

Abstract

According to crossability relations and fertility of hybrids, the various members of the genus Lens were grouped in two biological species, L. culinaris and L. nigricans. Members of different species are cross incompatible because hybrid embryos abort ca 2 wk after pollination. Hybrid seeds, which are rarely produced, are albino and die shortly after germination. When a mature plant is obtained, it is sterile as a result of irregular chromosome associations at meiosis. Within species, considerable chromosome repatterning occurs, but as a rule, F1 hybrids are easily obtained and are fertile or partially fertile. Three subspecies were defined in L. culinaris ssp. culinaris, which encompasses the cultivated lentils; ssp. orientalis, which represents the wild lentils with lanceolate stipules (cytogenetically, some accessions of this subspecies are closely related to ssp. culinaris); and ssp. odemensis, characterized by semi-hastate stipules that form horizontal positions on the stem. In conventional taxonomic treatments of the genus, ssp. odemensis is considered as L. nigricans. Lens nigricans is composed of two subspecies: ssp. nigricans has stipules that are considerably semi-hastate and dentate at their base and pointed upward in a parallel position to the stem; and ssp. ervoides has semi-hastate or lanceolate stipules and is distinguished by its smaller leaves, calyx teeth, pods, and seeds. The two subspecies rarely form mixed stands in nature, but their hybrids are partially fertile.