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Plant of the Month
Gymnocalycium uebelmannianum Rausch
Although Gymnocalycium is one of the most popular cactus genera, there are some species which are rarely seen in collections and this is a good example. It was described more than 40 years ago but has rarely been offered for sale by dealers. The best way to obtain the plant, like other gymnos, is by growing it from seed which you can buy from one of the specialist seed dealers.
The plant is a small growing species, similar to G. baldianum but with white or very pale yellow flowers. The spination is variable and quite open, showing the body beneath, some clones even have curly spines. I have found it to be sensitive in cultivation, the taproot being prone to rot if damaged when repotting, or if it is overwatered. The seedlings grow quite slowly, perhaps because they need to grow a taproot which, in their natural arid environment, would be necessary for water storage. In habitat, they grow in crumbling granite often in full exposure, an unusual situation for Gymnocalycium.
The species was first discovered by Walter Rausch in 1965 when he climbed up the Sierra Velasco above the small town of Pinchas in La Rioja, Argentina. It was a species that I really wanted to see in habitat, but I had been told that it was a long and difficult walk to get high enough on the mountain to see the plant. The opportunity presented itself in 2007 when I was in Argentina to research the book I was writing about Gymnocalycium. Having expected to spend a long day on the mountain, you can image my surprise to see a newly constructed road leaving the main road, Rte.75, and heading up the Sierra Velasco! Although incomplete, the road did go far enough to get us high up the mountain and we found the plant soon after we parked the car at over 2000m altitude. It was the perfect time for flowers and ripe fruits, so in warm sunshine we enjoyed a few hours looking at the many cacti in a beautiful unspoilt habitat.
Fig 1: Gymnocalycium uebelmannianum GC979.02 in cultivation
Fig 2: Gymnocalycium uebelmannianum GC979.02 in habitat
References Charles, G. (2009) Gymnocalycium in Habitat and Culture: 127-8. Self-published.
Pilbeam, J. (1995) Gymnocalycium. A Collector's Guide: 149. A.A.Balkema.
Rausch, W. (1972) Gymnocalycium uebelmannianum Rausch spec. nov. Succulenta 51(4): 62-64
Till, H. (1991) Gymnocalycium uebelmannianum Rausch. Gymnocalycium 4(1): 43-45
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