Diplosoma luckhoffii

Diplosoma luckhoffii (MRO209, east of Bitterfontein, Western Cape), a little over a year old from seed. Flower about 1 cm wide.

Diplosoma luckhoffii is a tiny winter-growing succulent from South Africa. The plants are completely dormant for much of the year, persisting as button-like bodies at or just below the soil surface, protected by a layer of dried up leaf tissue. When rain and heavy dew wet the soil in the cooler months, Diplosoma cracks out of its shell and sends up a pair of mushy green leaves, covered with sparkling, bubbly water-storage cells ("bladder cells"). Flowers are produced in mid- or late winter. The flowers often don't open very well, at least in cultivation, but set seed easily, and even self-pollinate sometimes.

Quartz flats in the northern Knersvlakte, where I collected Diplosoma seed in 2004.

Diplosoma luckhoffii is endemic to the Knersvlakte, a very clearly defined patch of desert only a few hours drive north of Cape Town. The Knersvlakte is characterized by low, rolling topography with frequent patches of snow-white quartz gravel. Not all of that quartz is entirely natural, and one occasionally runs across pieces that were shaped into blades by stone age people. Diplosoma, along with a diverse assemblage of other dwarf succulents in the Aizoaceae (mesemb family) and other families, lives only on soil with a dense cover of quartz rubble; the quartz moderates the temperature at ground level, and makes it possible for stubby little plants to survive the summer without cooking.

The cultivation of D. luckhoffii is fairly difficult. The plants are short lived, not usually surviving for more than three or four years even under ideal conditions, and as a consequence are never available except as seed, as far as I have seen. Diplosoma seed is almost as fine as dust, and should be sown in autumn on the surface of a mineral soil (sandy loam leavened with perlite, vermiculite and course sand) in the pot where they will stay permanently. Seedlings and mature plants alike demand brilliant sunshine, cool night temperatures and careful watering when active. The soil should dry out slightly at the surface between waterings, but remain slightly moist below ground at all times. During the warm-weather dormancy, pots of Diplosoma can be left dry, aside from an occasional misting on sunny days. When happy, Diplosoma sometimes flowers at the end of its first season, though more often the plants rot or terminally desiccate while still pinhead-size.

I have never heard of Diplosoma being successfully cultivated outside of a cool, airy and brightly-lit greenhouse, but I know someone who is trying it under fluorescent lights (right next to the tubes, for maximum illumination). It will be interesting if she succeeds!