Australian Orchid Foundation


Project: 339/2021

Title: Diversity and diversification of the Speculantha group (Tiny Greenhoods; Pterostylis subg. Speculantha [syn. Speculantha])

Applicant: Dr Russell Barrett, Dr Heidi Zimmer, Dr Mark Clements, Dr Katharina Nargar, Dr Lachlan Copeland, Dr Michael Mathieson, Mr Gavin Phillips, Dr Matt Renner

Institution:  National Herbarium of New South Wales, Australian Institute of Botanical Science, Royal Botanic Gardens & Domain Trust, Sydney NSW.

The Speculantha group (Pterostylis subg. Speculantha [syn. Speculantha]) currently includes 23 extant species. The group is confined to Eastern Australia, ranging from as far north as Maryborough in South East Queensland, south to Tasmania, and one species that extends from Western Victoria to South Australia. In 2010 there were only 10 species recognised in the Speculantha group, and over the past decade, recognised diversity has more than doubled with the description of thirteen species new to science. Many are known by relatively few collections, and species are usually distinguished by subtle differences in floral form. Current species concepts are based entirely on morphological characters and the correlation of morphological variation with population distribution is yet to be tested with molecular data.

Species in the Speculantha group have contrasting distribution patterns: ten are widespread, while thirteen are locally restricted. For example, the wide distribution of P. parviflora, which occurs from South-east Queensland to Tasmania, contrasts significantly with the restricted distribution of the allied P. glyphida, which is known from only one locality near Tallong, in New South Wales. Relationships among species, the occurrence and extent of hybridisation, and likely diversification processes are all unknown. This project aims to test both species limits and relationships at a population level using cutting-edge molecular techniques to generate thousands of genetic markers.