PHYLOGENETIC-RELATIONSHIPS IN THE CRASSULACEAE INFERRED FROM CHLOROPLAST DNA RESTRICTION-SITE VARIATION

A restriction-site analysis of chloroplast DNA from 44 species, repres enting 19 genera and all six subfamilies of the Crassulaceae was condu cted using 12 restriction endonucleases. A total of 969 variable sites was detected, 608 of which were phylogenetically informative and used in parsimony analysis. Estimated values of nucleotide sequence diverg ence were used to construct a distance tree by the neighbor-joining me thod. Maximum sequence divergence in the family was similar to 7%. Dif ferent tree inference methods yielded only moderately different topolo gies. The amount of support for the monophyletic groups obtained in th e Wagner parsimony analysis was evaluated by bootstrap and decay analy sis. There is very strong support for a basal division of the family, which separates the monophyletic subfamily Crassuloideae from all othe r taxa. Four of the six traditionally recognized subfamilies are indic ated to be polyphyletic. These include the Cotyledonoideae, Sempervivo ideae, Sedoideae, and Echeverioideae. The Kalanchoideae and the genera Cotyledon and Adromischus exhibit low levels of cpDNA sequence diverg ence relative to one another, suggesting a relatively recent radiation . The genera Sedum and Rosularia are indicated to be polyphyletic. Sed um comprises sister taxa of most of the other genera of the family.