Sunday, August 31, 2008

Tiny Blue Caladenia (Cyanicula caerulea)

I have the good fortune to live in a fairly large remnant of what is affectionately called "Bushland" here in south-eastern Australia. In the early 1950's a group of artists decided to drop out of society and flee to the hills northeast of Melbourne, Victoria. The land they could afford was approximately 160 hectares "out-the-back" of a grazing property. The farmer, who by the way passed on a few years ago, thought the land "useless for man or beast". The reason for this "uselessness" is easily explained; the underlying geology is a hard mudstone, the soil is practically non-existent, and the rainfall is low (approximately 500mm or 20 inches). The artists named this place Dunmoochin. The inevitable happened and the artists collective fell apart. The property was split and each of the members took up residency on their own bit. As they either moved on or died their little piece of dirt changed hands. Twenty years ago one of these blocks came up for sale and the opportunity presented itself for me to move in.

The vegetation is a reflection of the soils and the climate; sparse and slow growing, somewhat green in winter and parched, brown and crunchy in summer. Fortunately, these are the exact conditions that a great many geophytes (plants with underground storage organs) like. An impressive list of plants from the orchid, lily and sundew families occur on these dry somewhat forbidding hills. over the years that I have lived here, my neighbour, also a botanist, and I have recorded nearly 55 species of orchids alone! For 160 hectares this is a pretty impressive number, equal to some of the richest areas for orchid biodiversity in Australia.

Today a small group of us went for a walk for a few hours to look at the wildflowers on the "block". This is a regular feature of my life here and not a very onerous task as walking to anywhere on the property takes only a few minutes. We were in particular luck today. The season has been particularly kind in regard to rainfall and the plants have grown and flowered well so far this year.

One of the particularly delightful groups of orchids that occur here are plants in the genus formerly called Caladenia. Caladenia has fairly recently been split into several distinct genera. While there are arguments for and against lumping or splitting Caladenia the fact remains that there has always been several clearly distinct groups within the genus. The Spider Orchids (Arachnorchis) are the show ponies of the group with fantastically large spidery flowers in a wide range of colours sometimes with several starkly contrasting colours in one flowers. Most of the Arachnorchis are pollinated by less than observant male wasps that mistake the labellum of the flower for a female wasp. The fact that the orchid emits a fragrance remarkably similar to the pheromones of the female wasp may explain the lack of concentration of the male wasps.

A second and very small group separated off from Caladenia are the Blue Caladenia (Cyanicula). There are only ten species in the genus Cyanicula most of which occur in south-west Western Australia. In south-eastern Australia we have one relatively common member of the genus, namely Cyanicula caerulea (Tiny Blue Caladenia). Thankfully, this diminutive member thrives in just the conditions that are found here on the property. Well almost. More particularly C. caerulea grows on the hardest and driest of the slopes here and experiences the full blast of the afternoon sun on the northwest facing slopes. The moisture content of the soil on these slopes actually runs at a deficit for most of the year with only a few months in mid-winter to early spring when the top few centimeters of soils become slightly damp. I wouldn't use the term wet as most of the rainfall runs off and there is hardly any soil to hold moisture!

When we were out wandering around today we were actually focused on the valleys as we were looking for Greenhoods (Pterostylis) and Helmet Orchids (Corybus). It was such a nice afternoon we decided to see if the Cyanicula's were flowering. It was near the end of our walk so some of the others did not especially feel like climbing what are in fact very steep hills. I might add that the average age in the group was somewhere north of 50. If only we knew ahead of time what was awaiting us there might have been a bit more enthusiasm! As we neared the top of the slope the shrieks of "I found one" , "I found another one" and "look at these ones over here" rang out so loud that the laggards still in the valley suddenly found motivation and puffed their way upslope. The sight before us was magnificent. Literally hundred of these petite little blue orchids were scattered over the slope either singly or in small groups. The colours ranged from pale ice-blue to a clear dark blue and there was even one that was stark white. The white one may actually be another species, Caladenia praecox but this has to be confirmed. Being all of 5 cm tall it is hard to get a good shot but hopefully the photos below will give you some idea of the beauty of these delightful and remarkably tough little plants.

Tuesday, August 26, 2008

Cymbidium erythraeum and friends

A recent post on an international orchid forum dealt with the identification of Cymbidium erythraeum, in particular the form that goes under the name of C. erythraeum 'Paradise'. The poster questioned a plant he had in flower that was a supposed selfing of the 'Paradise' clone. As I had raised several seedling of this same selfing I agreed to put up a sample picture of one of the progeny. So here it is (left).

The 'paradise' clone varies from the ones commonly sold in Australia in that the flower spikes are gently arching or upright, the flowers are slightly smaller, the sidelobes of the lip are rounded and the flowers are widely spaced. The normal form has larger more shapely flowers, the side lobes of the lip are more or less sharply triangular, the flowers are more closely spaced and the flower spike is strongly arching.

The likely explanation for this divergence is the very wide range of the species in it's native habitat. According to Du Puy and Cribb (2007) "it extends from northern India from Kumaon, through Nepal, Sikkim and Bhutan to Myanmar and the western provinces of Shina (Sichuan, Xichang, Yunnan)". Their illustrations clearly show the differences of the plants found at the extremes of its range, Nepal and Yunnan.

One of the other confusing things in many cultivated plants, especially orchids, is the boggling array of hybrids, both natural and man-made, that blur the lines and cause many horticulturalists a great deal of angst. One of these hybrids, Cymbidium tracyanum x erythraeum, is commonly sold as either C. tracyanum or C. erythraeum. Although larger in size than C. erythraeum people not familiar with the 'wild' species can be terribly mislead. For a bit of clarity I have included pictures of C. tracyanum x erythraeum (left and below). This particular plant has as its parents the Indian form of C. erythraeum and C. tracyanum 'FCC'.

A friend of mine does 'artistic' pictures of my plants. You can find a couple of additional pictures of the original C. erythraeum 'Paradise' here. You can clearly see the arching stems and widely-spaced flowers. While C. erythraeum is not the largest or most spectacularly coloured of the Cymbidiums it does have a charm all of its own and a fragrance that is beautiful. One other point in it's favour is that the flowers last for months if the plant is kept cool and out of direct sunlight.

Another interesting site that has pictures of C. erythraeum and a range of other species is Stephen Early's webpage. You can find it here. Check out the individual species but also the "New and Doubtful" section where he deals specifically with the problem listed above. If you are willing to spend a heap of money on a book that is published mainly in Chinese check out The Genus Cymbidium in China by Liu Zhong-jian, Chen Sing-chi, Ru Zheng-zhong and Chen Li-jun in 2006 by They have a few pictures of C. erythraeum as well. Some are mislabeled as C. flavum, which is in fact just an albino form of C. erythraeum.


Du Puy, D. and Cribb, P. (2007). The Genus Cymbidium. Kew Publishing, Royal Botanic Gardens, Kew.