DISTRIBUTION OF ALKALOIDS AND TANNINS IN THE CRASSULACEAE

Alkaloid and tannin levels of 36 species of the Crassulaceae were comp ared. The taxa investigated were Crassula multicava, Echeveria venezue lensis, Pachyphytum compactum, Kalanchoe (two sop.), Bryophyllum daigr emontianum, Sedum (23 spp.), Aeonium (four spp.) and Sempervivum (thre e spp.). Apart from the alkaloidal species of Sedum, only E. venezuele nsis was found to contain piperidine alkaloids, i.e. pelletierine and N-methyl pelletierine. Proanthocyanidins (condensed tannins) and gallo yl esters were found in all genera, but they were absent from six out of 11 Sedum species containing piperidine alkaloids. The results indic ate a dichotomy between the distribution of alkaloids and tannins, whi ch is in good agreement with the major evolutionary trends within the family as inferred from chloroplast DNA restriction site variation. Th e distribution of alkaloids appears to be limited to the ''Acre'' line age, which comprises the Asian, Eurasian and American Sedum species wi th a reticulate testa as well as the Central American Sedoideae and Ec heverioideae. The parallel occurrence of alkaloids and a complex of ap parently primitive flower and seed characters in the terminal ''Acre'' clade indicate the derived rather than the primitive condition of the latter features. The most parsimonious explanation for this marked in consistency is a reversal of the floral structure at the basis of the ''Acre'' lineage, mimicking the floral structure of ancestral angiospe rms.