Studies in Rubiaceae. II. Spermacoce hispida Linn., Guettarda speciosa Linn. and some cytomorphological considerations

Abstract

The development of embryo-sac and embryo has been described in Spermacoce hispida and Guettarda speciosa. The haploid numbers, Spermacoce (n=28) and Guettarda (n=22), previously reported, are confirmed. Meiosis is described in some detail. The development of the strophiole has been traced and it is considered to have little phylogenetic importance. The suggestion previously made that 11 was the basic number of the family is confirmed by data gathered in this paper. The evolution of the chromosome numbers in this family is discussed in the light of data known in connection with nucellar evolution. A correlation is established between the two and a few tentative schemes of nucellar and chromosomal evolution suggested.