Petalochilus is one of the proposed new genera in the breakup of Caladenia in the Orchidaceae family. It is not recognized as a genus universally. Flowers have short broad segments with pink or white petals, a narrow leaf, and a lip with rows of free calli. It is very like Stegostyla except that the flowers are not glandular outside and the dorsal sepal is suberect. The column often has red bars and the calli are smooth. The common name of this group is Fingers.
The Species Orchid Society of Western Australia hosts a lot of information online about Australian orchids here.
The Australian terrestrial orchids are notoriously challenging to grow, although some enthusiasts are starting to achieve success by cultivating the symbiotic fungus that many of the orchids require in order to grow. Very careful fertilization is required to keep the fungus and orchid in balance. There's a good discussion of the relationship here.
Petalochilus carneus syn. Caladenia carnea or Pink Fingers occurs in almost all Australian states, New Zealand, New Caledonia, Indonesia and Malaysia. It is very variable in size (5 cm to 25 cm high) and color ranging from white to pale pink to deep pink. It occurs in many different habitats. The rear sepal is erect and the four other segments spread forwards like the fingers of a hand. It has 1 to 4 flowers on a wiry scape that are 2 to 3 cm across. The lip has dark red bars and two rows of yellow calli. Photographs taken October 2007 in the Grampians by Mary Sue Ittner.
Petalochilus pusillus syn. Caladenia pusilla or Tiny Fingers is a species that is quite small. It is found in southeastern Australian states growing in heathland or open forest in sandy soils. Photographs taken October 2007 near Apollo Bay by Bob Rutemoeller and Mary Sue Ittner.