Orchidaceae

OrchidaceaeOrchidaceae Index Caladenia barbarossa (Dragon Orchid) Caladenia bryceana subsp. bryceana (Dwarf Spider Orchid) Caladenia corynephora (Club-lipped Spider Orchid) Caladenia integra (Smooth-lipped Spider Orchid) Caladenia latifolia (Pink Fairies) Caladenia lobata (Butterfly Spider Orchid) Caleana major (Flying Duck Orchid) Caladenia melanema (Ballerina Orchid) Caladenia polychroma (Joseph’s Spider Orchid) Caladenia pulchra (Slender Spider Orchid) Caladenia pusilla (Tiny Caladenia) Caladenia serotina (Christmas Spider Orchid) Caladenia tessellata (Thick-lip Spider Orchid) Cephalotus follicularis (Western Australian Pitcher Plant) Cryptostylis ovata (Slipper Orchid) Dendrobium kingianum (Pink Rock Orchid) Dendrobium speciosum (Rock Orchid) Drakaea glyptodon (King-in-his-carriage Orchid) Drakaea livida (Warty Hammer Orchid) Elythranthera emarginata (Pink Enamel Orchid) Epiblema grandiflorum (Babe-in-a-cradle Orchid) Ericksonella saccharata (Sugar Orchid) Glossodia major (Wax-lip Orchid) Leptoceras menziesii (Rabbit Orchid) Microtis cupularis (Cupped Mignonette Orchid) Paracaleana nigrita (Flying Duck Orchid) Pterostylis cheraphila (Floodplain Rustyhood) Pterostylis ciliata (Hairy Rufous Greenhood) Pterostylis picta (Painted Rufous Greenhood) Rhizanthella johnstonii (Southern Underground Orchid) Spiculaea ciliata (Elbow Orchid) Thelymitra antennifera (Lemon-scented Sun Orchid) Thelymitra sp. Ongerup (Orange Sun Orchids) Thelymitra speciosa (Eastern Queen of Sheba’s)

Orchids, from the family Orchidaceae, are a diverse and widespread group of flowering plants with blooms that can be tiny and almost inconspicuous to large colourful and fragrant blooms. Orchidaceae is one of the two largest families of flowering plants, along with the Asteraceae.

In Australia there are more than 100 genera of orchids, with more than 1,700 of the 25–30,000 species in the Orchidaceae family known globally, with the majority of the Australian orchids being ground-living and found nowhere else in the world.

Unfortunately, Australia has a high rate of orchid extinction, thought to be as high as 25 per cent of our native orchid having become or becoming extinct. In part, this is due to their vulnerable of their symbiotic relationships with specific types of ‘mycorrhizal’ fungi to grow and germinate, and many of the native orchids being pollinated by a unique species of pollinator.

The Taxonomy of the Orchid Family, is a story all on it’s own, with a number of classification systems. It is the classification, published in the book ‘The Orchids: Natural History and Classification’ that is widely accepted by botanists and growers. This is based largely on the system of Robert Louis Dressler, an orchid specialist and adjunct curator at the Florida Museum of Natural History. The initial scheme of 1981 has been modified in 1986, twice in 1990, and then again in 1993. This is the most comprehensive classification at the moment, relying heavily on morphology and a few key characters, such as anther configuration and pollinarium structure.

The orchid family (Orchidaceae) is subdivided into several subfamilies, and then into tribes, subtribes, alliances and then genera.

According to Dressler, there are 5 subfamilies, 22 tribes, 70 subtribes, about 850 genera and 20,000 species in this family. Since then several thousand orchids have been described.

Whilst some orchids mainly or totally rely on self-pollination, many rely on insects such as bees, flies and butterflies. For example in Australia, a group of bees known commonly as “Bush Bees” that include the Sugarbag Bee (Tetragonula carbonaria), are known to pollinate orchid species.

Other orchids take a different tactic, such as Drakaea livida who use a form of what is described as “sexual deception”. The labellum of Drakaea livida is similar in shape and scent to the flightless female thynnid wasp (Zaspilothynnus nigripes). This lures the male of the species to attempt to mate, but instead pollinates the orchid.

Orchids, including the many hybrids varieties are often on display at orchid shows, botanic gardens and specialist dealers. Check out our section on orchids at the Royal Botanic Garden Sydney.