Homostyly in heterostyledOldenlandia umbellata L., a species of the family Rubiaeeae is described. Homestyles are of the short styled type. Measurements of homostyles are compared with the heterostyles. On the basis of self fertility the homostyles are named fertile and infertile. Results of pollination experiments in various combinations carried out within the heterostyles, in the homostyles and heterostyles are given. Among the incompatible crosses of heterostyles (both self and cross) the incompatibility is absolute in thrums while it is slightly relaxed in pins. Incompatibility is not observed in the bud pollinations. In the compatible pollinations the cross pin X thrum is more fertile than its reciprocal. The fertile homostyle is the most fertile. Among the crosses, the cross pin X fertile homostyle is most fertile while the cross infertile homostyle X pin is the least fertile.