Open Access

Ross Goldingay, Michiala Bowen

• The breeding systems of the rainforest shrubs Hicksbeachia pinnatifolia and Triunia youngiana were studied in north-east New South Wales, where the former is listed as a vulnerable species. Hicksbeachia pinnatifolia flowered in winter and spring, and produced an average of 36 inflorescences per plant with 155 flowers per inflorescence (5580 flowers per plant). Inflorescences initiated and matured only a small number of fruits (c. 1–2 per inflorescence) in self-pollinated and open-pollinated treatments. This compared to about 17 fruits initiated and 4 fruits matured per inflorescence when cross-pollinated. Triunia youngiana flowered in spring and produced an average of 3 inflorescences per plant containing 23 flowers per inflorescence (69 flowers per plant). Plants were unable to initiate any fruit in autogamy and self-pollinated treatments. Plants in a cross-pollination treatment produced over three times as many fruit (3.5 matured per plant) compared to a control treatment (0.8 per plant), suggesting that plants were pollen-limited. Both treatments experienced substantial (80%) fruit abortion. These results indicate that Triunia youngiana is self-incompatible whereas Hicksbeachia pinnatifolia appears to be partially self-compatible.