Caladenias have recently been regrouped with some species being split into several groups. I am an orchid novice and I'm not going to attempt, at this stage, to unravel the mysteries of taxonomy, but will just accept what the experts profess.
Formerly known as "Ladies Fingers", Caladenias are now referred to as "Finger Orchids" (another example of "political correctness" gone mad). The "fingers" are the lateral sepals and petals resembling a hand of four spread fingers.
Cyanicula caerulea, formerly Caladenia caerulea, is one of the more easily-identified Finger Orchids and is often one of the first to appear in spring. I found it in massed displays in disturbed rocky soil in Werakata National Park near Cessnock in the lower Hunter Valley in late winter and early spring.
It has a single bright green basal leaf to about 70mm long by 4mm wide which tends to lie flat on the ground. Cyanicula caerulea, commonly called Blue Caladenia, bears a solitary flower on a dark scape (stem) from about 50mm to 130mm high. The flower is sky blue to purplish, and covered in minute dark blue to purple glands (hairs) on the outside.
The labellum has a white or yellow tip and is marked with dark bands. There are two rows of stalked yellow-headed calli.
The only other blue Caladenia in eastern Australia is Bluebeard Orchid or Blue Fairies (Pheladenia deformis, formerly Caladenia deformis) which has 4 to 6 irregular crowded rows of stalked calli densly covering the labellum which distinguishes it from Cyanicula caerulea. I have not seen Pheladenia deformis in the Hunter Valley and I am not aware if it is found here.
Cyanicula caerulea is also found in Victoria, ACT and Queensland and it flowers between July and September.
Notice there is no green on the column at all. This photo of Cyanicula caerulea (Blue Caladenia) shows the vertical burgundy pattern on the interior of the column and purple colouration on the underside of the labellum.
Petalochilus carneus, formerly Caladenia carnea, and commonly called Pink Fingers, is a more variable species. The colour variation ranging from pale to dark pink through to white and white tinged with pink is well illustrated by Denis Wilson on his Nature of Robertson blog. As yet, I have only observed dark and light pink specimens.
A picture of a pale pink Petalochilus carneus (Pink Fingers) with two flowers. Note that the dark pink banding can be seen through the green of the column and the white of the labellum.
The most noticable difference in these next two white Caladenias to the novice orchid observer is the colour of the column.
Petalochilus pictus (formerly Caladenia picta) is also referred to as White Fingers or White Caladenia. It can flower anytime between late May and October, and although predominantly white, it can also be tinged with pink.
The red of the column interior is most commonly solid, but can occasionally be split in to two sections (but does not appear in several bands).
A pink-tinged Petalochilus pictus.
My Orchid biology blog entry briefly and simply describes orchid parts and their functions.
For an easy-to-understand description of orchid pollination, I suggest reading How orchids are pollinated by Denis Wilson of Nature of Robertson. Here are a couple of my native ground orchid pictures relating to pollination.....
This fly has probably entered the labellum gap of Petalochilus catenatus seeking the nectar often found on the large basal glands. The insect can turn around as the labellum is hinged and mobile, and in its efforts to escape it can be noticed the thorax is touching the pollinia, so the next time the insect attends another flower, pollination should occur. As the stigma is situated immediately below the pollinia sac, the insect, when turning, tends to scatter the pollinia on to the column and stigma.
The pollinia have been dislodged from the top of the column in this Petalochilus carneus, and on being subject to the air, has become mealy (dry) and dropped on to the base of the labellum giving the illusion of a second set of pollinia. This procedure occurs in the genus Thelymitra (Sun Orchids) quite frequently.
My thanks to members of Australasian Native Orchid Society who helped me distinguish between Petalochilus catenatus and Petalochilus pictus as well as clarifying some aspects of pollination. I hope this brief description, together with my photos and links, will assist other novice orchid admirers identify Caladenias that they observe.
These delicate and pretty little native ground orchids are worth seeking, and I am always delighted to find them popping up in grassy open forest and amongst roadside vegetation.