Gynodioecy in native New Zealand Gaultheria (Ericaceae)

The breeding systems of Gaultheria na- tive to New Zealand were investigated. Gaultheria antipoda and G. depressa var. depressa populations contained only hermaphrodites. Populations of five other taxa were found to be gynodioecious in natural populations, with 4-67% females, and evidence from the literature and herbarium sheets suggests that an additional five taxa are gynodioecious. Compari- sons of flower parts, flower number, and fruit set of females and hermaphrodites in three taxa revealed few significant differences. Corollas of G. panicu- lata were smaller in females, but style length and flower number per raceme were not significantly different between the two sexes. Flower number per raceme and fruit set also did not differ significantly between females and hermaphrodites of G. crassa and G. oppositifolia. The similarities in fruit set between the sexes (always within 5% of each other within populations), combined with high female frequencies, suggest that male sterility is caused by cytoplasmic factors. Gynodioecy is widespread but not ubiquitous in New Zealand Gaultheria.