Tuesday, 2 October 2007

#30 Spring orchids

Spring is warming up and ground orchids are becoming more scarce in the Hunter Valley, but I've observed many from the Caladenia group in varying shades of blue, pink and white. Caladenias are dainty terrestrial orchids that are a joy to see bobbing in the breeze, but they are often not easy to identify. I am devoting this blog entry to describing species in the hope of making recognition easier for others.

Cyanicula caerulea has a single bright blue flower about 25mm across. The labellum (lip or tongue) has dark blue bars and two rows of yellowish calli.

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.

The identifying feature of Petalochilus carneus in all its shades is the dark pink horizontal banding of the upper surface of the labellum and the inner surface of the column. The exterior of the column is green. The labellum has two rows of yellow calli and a yellow tip.

Petalochilus carneus has one erect dark green leaf to 150mm long by 4mm wide, and a thin green scape to 250mm high. Plants can bear one or two flowers. This species is wide-spread and found in NSW, Qld, ACT, Vic, Tas and SA, and it flowers between August and October.

The dark pink or red markings on the labellum and column are a feature of Petalochilus carneus. Notice the green exterior of the column and the yellow tip of the labellum.


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.

The column of Petalochilus pictus (left) has a green exterior and red interior, while Petalochilus catenatus (right) has a column that is green inside and out.























Petalochilus catenatus, (formerly Caladenia catenata and Caladenia alba), is commonly called White Fingers or White Caladenia. It generally flowers from June to October and is found in NSW, Qld, Vic and SA.

It has one dark green erect linear leaf up to 120mm long by 4mm wide. The green hairy scape can be up to 300mm tall holding one or two white, or occasionally pink-flushed, flowers. There are two rows of stalked club-headed yellowish calli on the white, yellow-tipped labellum.

Green column of Petalochilus catenatus


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.

13 comments:

Evan said...

Here's my favourite orchid find of the season: Chiloglottis formicifera

http://www.flickr.com/photo_zoom.gne?id=1422901320&photo_page=1&size=o

Evan

Gaye from the Hunter said...

hello Evan,

the 'ant' or 'wasp' orchids are fabulous, and your find is a beauty, especially as you have shown the detail up close.

I'll put a direct link to your picture for others:

Evan's pic of Chiloglottis formicifera

I think I might have found that one too, Evan, and I'll compare it to my pictures.

Regards
Gaye

Denis Wilson said...

Hi Gaye
Terrific photos of the "Caladenias".

I am madly jealous of the photo of the fly being dobbed by pollen by the flower. It is terrific. Thanks for linking to my post on that subject, as your photo is a perfect illustration of what I was trying to explain.

I still have not seen the Blue Caladenia, but I did catch the tiny purple "Glossodia minor" again this year. I know of only one place (locally) where they grow, but they flower there every year.

I think Evan's name for the Ant Orchid is correct, but location is important to know. Similar looking flowers are sometimes classified differently for reasons which are not obvious even in good photos. Certainly the shape of the calli and fact that they go all the way to the tip of the labellum is consistent with that name. They certainly are amazing plants, and Evan's photo is very good.

The double "eyes" on the head on the "pseudo-insect" and the horizontal angle of the lateral sepals all are typical of that species.

Denis

Gaye from the Hunter said...

hello Denis,

as you can imagine, I was very excited to find the fly in the orchid, and thrilled to get one half-decent photo of the event. I had my compact camera with me which is only 3.2 megapixels, so severe cropping has not produced a sharp image.

Even when I've seen countless numbers of particular orchids, I like to take a reasonable look just in case I can observe a pollinating insect or something peculiar like the dislodged pollinia. I will admit that I didn't notice the dislodged pollinia until I viewed the photo. My eyesight is not the best, but as I only where glasses for close work and not walking/driving etc, I don't always take them on walks.

Regards,
Gaye

Evan said...

Hi Denis,

The wasp orchid was taken at the Hunter Botanic Gardens, in one of the natural bush sections (not planted out). There was a section that was absolutely full of them, but it was over a very small area (< 1 square m).

I was taking a photo of a pink Petalochilus? when I noticed it, because it isn't particularly vibrant.

Evan

Gaye from the Hunter said...

Evan, my latest wasp orchid find (which, on close comparison with your photo seems to be the same species) was also on one of the bush trails at the Hunter Region Botanic Gardens, and was also just a small patch of about 1sqmt.

I found Pink Fingers over the other side of the swamp boardwark (which starts at the palm garden), along with Tall and Nodding Greenhoods.

On my most recent walk at the Botanic Gardens (about 4 weeks ago) I found 7 species of ground orchid flowering.

I hope to go again shortly before it gets too hot. If you want specific directions to find some of the finished species next season, let me know via email on my blog home page.

Cheers
Gaye

Evan said...

Ha, we may have found the same patch! It was on a path after the wetland bridge. If you keep going (heaps further down, this patch was towards the start), you come out into the clearing where the powerlines go through.

Evan

Evan said...

I also heard a vulnerable species of frog (Crinia tinnula) when I was there. It isn't on the species list for the gardens either. I would love to go frogging at the wetlands, but they lock it up at night.

Evan

Gaye from the Hunter said...

Evan,

it wouldn't hurt to ask if a night visit would be possible for research purposes.

I know that the Botanic Gardens is starting projects to record species within the grounds, and as most are volunteers, they might be very pleased to have contact with you.

On a recent visit to the Gardens, I was talking to the chairman(woman), Jan, and I have offered to help them with details and photos of the fungi and orchids that I have found within the Garden grounds.

Here is a link to Hunter Botanic Garden contact options

Gaye

Denis Wilson said...

Hi Evan and Gaye
Sounds like you both found the same group of plants, or similar groups in roughly the same place.
Evan, my point about location was that some areas, especially up around Barrington Tops appear to be "isolated" and so, have different species there.

I agree with Gaye's comment about the Hunter Botanic Gardens. I know from my experience at the Botanic Gdns in Canberra, the "Friends" would welcome an approach from someone able to identify frogs, especially ones not listed. Give it a go. You might end up being their consultant "Frog Person". You could do worse.

Cheers to both of you.

Denis

Evan said...

Hi guys,

I just got a reply from the gardens, and they sound delighted to let me have a look. I will hopefully be doing a couple surveys in November.

Evan

Gaye from the Hunter said...

Good news indeed, Evan. Have fun with it.

norman said...

Hi Evan & Gay,
We visited your garden last week and took this picture : http://i760.photobucket.com/albums/xx242/norman_ho/webpics/flower1.jpg
Could you tell us the common name and botanical name of this plant please.

Thanks.
Norman