Taxonomy of Thelymitra

Project summary

The orchid genus Thelymitra currently consists of about 130 species. The genus occurs predominantly in Australia, where there are at least 110 species.Thelymitra reaches its greatest diversity in the wetter habitats of south-western and south-eastern Australia, with only a few species found in northern Australia. There are also a few species in the Philippines, Indonesia, New Guinea and New Caledonia, and about 20 species in New Zealand.

The aim of this project is to identify and describe new Australian species ofThelymitra. Dried and spirit herbarium collections are being studied, as well as fresh material collected from field work in southern Australia.

Members of the genus Thelymitra (commonly called Sun Orchids) are perennial ground orchids, which die back to underground tubers during the warm dry months of the year. They have a single basal leaf and an erect inflorescence with up to 40 flowers. The flowers may be self-pollinating or insect-pollinated and open only on warm to hot days. Flowers are usually blue, pink, yellow or white, but may have darker spots or blotches or prominent longitudinal veins. The labellum of most species is undifferentiated from the other perianth segments, which is unusual in the orchid family.

The column structure, particularly the post-anther lobe, has traditionally been the main way in which species are distinguished from each other, and this is certainly important. However, cryptic species have been found by studying other characters such as the leaves, bracts, flower size, flower colour and other aspects of the column such as the structure of the hairs on the lateral lobes. Habitats and flowering times are also proving useful in identifying new species.

Project team

Publications

Jeanes, J.A. (2009). Resolution of the Thelymitra variegata (Orchidaceae) complex of southern Australia and New Zealand. Muelleria 27, 149–170.

Jeanes, J.A. (2006). Resolution of the Thelymitra fuscolutea R.Br. (Orchidaceae) complex of southern Australia. Muelleria 24, 3–24.

Jeanes, J.A. (2005). Thelymitra reflexa (Orchidaceae), a new rare species from Victoria, Australia. Muelleria 21, 87–90.

Jeanes, J.A. (2004). A revision of the Thelymitra pauciflora R.Br. (Orchidaceae) complex in Australia. Muelleria 19, 19–79.

Jeanes, J.A. (2001). Resolution of the Thelymitra canaliculata R.Br. (Orchidaceae) complex in southern Australia. Muelleria 15, 75–89.

Jeanes, J.A. (2000). Two new species of Thelymitra (Orchidaceae) from southeastern Australia. Muelleria 14, 91–97.