New taxa in Commelinaceae

Two new names are published: Gibasis venustula subsp. robusta D. R. Hunt and Tradescantia poelliaeT). R. Hunt.     

New taxa in Commelinaceae

Two new names are published: Gibasis venustula subsp. robusta D. R. Hunt and Tradescantia poelliaeT). R. Hunt.     

Contributions to the Cytotaxonomy of the Commelinaceae. Gibasis linearis and its allies

Species of the Gibasis linearis alliance collected in Mexico in 1976 are shown to have a chromosome constitution of x = 6, but x = 5 has also been found in some populations of G. rhodantha and G. speciosa. These two basic numbers are associated with distinctive karyotypes, 2M + 4A and 3M + 2A respectively, which show a Robertsonian relationship with each other. The existence of 2n = 22 in G. speciosa , combining both basic numbers at the amphidiploid level provides evidence of pairing between metacentrics and acrocentrics in such a way as to substantiate the view that fusion or fission of chromosomes is responsible for the modification of basic number. This survey provides a basis for other studies which will determine the chromosome relationships of the species irrespective of chromosome number in this family.