SYSTEMATIC IMPLICATIONS OF POLLEN MORPHOLOGY IN CARYOPTERIS (LABIATAE)

Caryopteris, an Asian genus of 16 species, has greater pollen diversit y than has been reported in any other genus of Labiatae. The pollen mo rphology of 15 species is documented here. Three pollen types are dist inguished on the basis of exine structure and sculpturing: spinulose t o spinose with slender, finely divided columellae (alternatively inter pretable as an expanded tectum); verrucate with a well defined tectum and thick, sparsely branched columellae; and suprareticulate to micror eticulate with moderately thick, sparsely branched columellae. Thirtee n species are tricolpate, Caryopteris divaricata is triporate, and C. nepalensis is 6-pantocolpate. Pollen morphology and correlated variati on in floral and fruit morphology suggest that Caryopteris comprises t hree primary phenetic groups. However, two recent cladistic analyses ( one based in part on the pollen features documented here) indicate tha t the genus is para- or polyphyletic and that only one of the three ph enetic subgroups is clearly monophyletic. Recircumscription of the gen us is recommended, but this should await completion of current studies that will facilitate its subdivision into monophyletic taxa.