HELEN M. STACE¹ and D.F. CAMERON²

CSIRO, Division of Tropical Crops and Pastures:
¹Davies Laboratory, Townsville, Qld. 4814.
²Cunningham Laboratory, St. Lucia, Qld. 4067.

Abstract

Stylosanthes hamata (L) Taub. sensu stricto is a perennial diploid (2n = 20) of the Caribbean islands and adjacent mainland regions of Florida, Colombia, Venezuela with disjunct populations in north-east Brazil. The cultivar 'Verano' is a tetraploid (2n = 40) as demonstrated cytologically and allozymically, and is not correctly included in S. hamata although it is a tetraploid derivative involving S. hamata. Two other tetraploid taxa are listed in the CSIRO collection as 'S. hamata'. One from Guatamala is somewhat similar to the 'Verano'-type tetraploids. The other belongs to the S. scabra tetraploid complex and should be excluded entirely from S. hamata and its derivatives. The undescribed tetraploid taxon which includes cv. 'Verano' requires recognition at the species level.