Autotetraploidy in Cucumis zeyheri and a derived new species C. diniae (Cucurbitaceae)

Three cytotypes at the diploid and tetraploid level of Cucumis zeyheri were investigated by means of multivariate morphological analysis, for pollen structure and by analysis of meiosis. Two main groups emerged after principal component and cluster analyses. Diploids and autotetraploids were placed in one group designated as C. zeyheri , the allotetraploids formed a separate group. Autotetraploids showed a mean number of one quadrivalent per pollen mother cell, together with 10% tetra‐porate pollen grains indicating an autoploid origin. The allotetraploids may have originated from polyploidization after hybridization of C. zeyheri and C. prophetarum. They are described as the new species C. diniae , which differs from C. zeyheri in leaf colour and width of leaf lobes, and from C. prophetarum in the concolour fruits. Leaf shape and leaf incision is intermediate between the parents.