Generic limits within the family Sapotaceae are problematic with the number of genera recognised varying from 122 (Aubréville, 1964) to 53 (Pennington, 1991). A a key reseach theme of the RBGE Sapotaceae research programme is on the production of robust molecular phylogenetic frameworks in which problematic generic limits can be addressed.
The Tribe Isonandreae
Relationships between genera and delimitation of genera in the largely South East Asian tribe Isonandraea are unclear. Two of the largest genera, Palaquium and Madhuca, both of which have over 100 species, are poorly sampled in molecular phylogenies. A key focus of our research todate is increasing the sampling within these genera (and the tribe in general) so that a better understanding of relationships can be produced. This will provide the framework for monographic publications of genera in this group.
The Subfamily Chrysophylloideae
Generic limits in this subfamily are particularly poorly circumscribed. Swenson, Richardson and Bartish (2008) demonstrated that many morphological characters are homoplasious and indicated that genera will need to be redefined. Additional samples are being added to a molecular phylogeny that will be used to improve generic delimitation.
Swenson, U., RICHARDSON, J.E. and Bartish, I.V. 2008. Multi-gene phylogeny of the pantropical subfamily Chrysophylloideae (Sapotaceae): Evidence of generic polyphyly and extensive morphological homoplasy. Cladistics 24: 1-26.
The Genus Payena
A full species level molecular phylogeny of the South East Asian genus Payena is currently in production. This is a collaborative effort with Dr Joan Pereira of the Sabah Forestry Department.