Systematic study of the generic patterns in the tribe Ingeae : (Leguminosae: Mimosaideae, with emphasis on Zygia-caulanthon)

Rico Arce, Maria de Lourdes (1989) Systematic study of the generic patterns in the tribe Ingeae : (Leguminosae: Mimosaideae, with emphasis on Zygia-caulanthon). University of Southampton, Doctoral Thesis.

Record type: Thesis (Doctoral)

Abstract

A systematic study of the Ingeae tribe is presented, with the aim of helping to delimit and elucidate the generic patterns within the Ingeae tribe and the relationships of the Zygia-Caulanthon (Zygia-unijugae and Zygia-plurijugae) group. This investigation involved the application of two different numerical methods, cluster analysis for a phenetic approach, and parsimony methods for a cladistic study. The programs LINKAGE (single linkage clustering) and CHARANAL (character analysis), were used for the phenetic analysis. The programs PAUP, CONTREE and MacClade, were used for the cladistic analysis. Herbarium material of representatives of most genera from the tribe Ingeae were studied. Seedling and pollen data was gathered and recorded for some of the species under study. The genera Zygia-unijugae, Cojoba, Pithecellobium and Inga-Affonsea formed phenetically well-defined clusters. Albizia species could not be circumscribed into one group. Species of Lysiloma, Havardia and Calliandra were phenetically grouped into one assemblage, and Zygia-plurijugae showed a reticulate phenetic pattern. A list of sixteen highly correlated characters for the Ingeae classification was produced. Cladistically, Zygia-unijugae species were placed in a monophyletic group and its sister groups were Callozygia, Pithecellobium, Cedrelinga and Inga-Affonsea. The putative species of Zygia-plurijugae were diagnosed as paraphyletic. One assemblage of Zygia-plurijugae was distantly related to species of the Zygia-unijugae. Among the characters studied seed coat, pleurogram, seedling and pollen exine structure proved to be good synapomorphies for the Ingeae classification. An informal classification based on a selected cladogram is presented and compared with a previous classification. A discussion is given, supported with phenetic and cladistic evidence, and suggestions for the generic circumscriptions are provided.