Taxonomic studies in the genus Gaultheria L. and related genera (Ericaceae)
The genera of the Gaultheria group of the tribe Andromedeae (Ericaceae) have been studied. These genera are Gaultheria L. (including Chiogenes Salis.), Pernettya Gaud., Leucothoe Don, Zenobia Don, Diplycosia Bl., Pernettyopsis King et Gamble and Tepuia Camp. Morphological, anatomical, chemical and cytological characters have been used to clarify generic limits and to construct a subgeneric classification of Gaultheria. Chemical and cytological characters were found to be of limited taxonomic use because of the unpredictable infraspecific variation of the former and the virtual absence of variation in the base chromosome number for the latter. Chiogenes and Pernettya are not sufficiently distinct from Gaultheria to be maintained as separate genera. Appropriate binomials have been proposed, within the genus Gaultheria, for all of the species of Pernettya. Leucothoe and Zenobia, although undoubtedly close to Gaultheria, are maintained as separate genera. The genus Gaultheria has been classified into ten sections (one with two subsections) and 22 series. Each taxon has been described and a diagnostic key to the sections and series has been provided. Field studies in Ecuador have highlighted aspects of the ecology of Gaultheria and Pernettya, particularly their preference for highly disturbed habitats. A previously undescribed hybrid between Gaultheria reticulata and Pernettya prostrata has been found. Closer study of the stamens and anthers of a number of species of Gaultheria has revealed a high incidence of male sterility indicating that gynodioecism may be more common in the genus than previously suspected. Previous studies and observations in the field suggest a high incidence of self-pollination.