Botanic Gardens Trust, Sydney, Australia

New Species and phylogeny in Restionaceae

Dr Barbara Briggs - Honorary Research Associate
Carolyn Connelly - Laboratory Manager
Adam Marchant

Restionaceae is an almost exclusively southern Hemisphere plant family, with centres of diversity in the south of Western Australia and in South Africa. Mostly these sedge-like plants grow in seasonally wet habitats, although some are found in semi-arid regions. All occur in areas of low soil fertility. The great majority are dioecious, with separate male and female plants, and they are wind-pollinated, with small flowers. As part of a long-term study, we have investigated the Australian species and their morphology and used DNA data to investigate their relationships. Twenty-two named species are native to New South Wales, including four species that are being newly described as a result of this study.

Continuing the project to describe the Australian species, the features and distributions have been clarified for a further thirteen species. Descriptions of nine new species of Lepyrodia, one of Sporadanthus and three of Lepidobolus have been submitted for publication in our journal Telopea. One of the publications is jointly authored by Dr Kingsley Dixon of Kings Park and Botanic Garden, Perth.

The detailed structure of seed surfaces has been important in distinguishing the new species, since some species are very similar but have very different seeds. They were studied by Carolyn Connelly using scanning electron microscopy. Carolyn also first recognised the distinctiveness of one of the Lepyrodia species and it will be named after her.

Chloroplast DNA data obtained by Dr Adam Marchant have shown that the current classification of several genera of Restionaceae does not appropriately reflect their relationships. Some future changes in classification will therefore be necessary.

Adam is continuing to develop more comprehensive DNA data for Australian species while Barbara is investigating species distinctions in several genera and preparing descriptions of a further nine new species of Leptocarpus. Further studies of Restionaceae seeds are also planned.

Seed of an undescribed Lepyrodia species. Photo: Carolyn Connelly