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Disphyma crassifolium subsp. clavellatum - Rounded Noon-flower
The botanical name of Disphyma crassifolium subsp. clavellatum describes this common plant of Australia and New Zealand. However if you were to refer purely to Australian species you could simply call it Disphyma crassifolium, as the Australian Disphyma genus has only one species with the single subspecies clavellatum. The only other subspecies, Disphyma crassifolium subsp. crassifolium occurs in South Africa, which clarifies and separates it from the kindred Australian and New Zealand species.
The Rounded Noon-flower belongs to the Aizoaceae family along with many other ‘Pigface’ plants like the similar flowered Carpobrotus genus. Disphyma crassifolium can be encountered in sandy hollows, on limestone, saltlakes and clay flood plains, particularly if saline, and commonly grows in association with other fleshy leaved salt tolerant species. Carpobrotus spp. generally grow in drier situations on deep calcareous and non-calcareous sand, elevated fine clay/sand mallee soils and rocky outcrops.
If not familiar with Disphyma and Carpobrotus plants, they can be a little confusing to identify, although easily separated by a few distinctive features; Disphyma has rounded leaves that root at the nodes, whereas Carpobrotus have angled ones and often do not root at the nodes, particularly the outermost ones. Also the flowers of the former are held above the fleshy foliage on long stems, whereas the latter are without stems (sessile) or nearly so and nestle between a couple of fleshy angular leaves. Lastly, the Disphyma fruits are dry, whilst Carpobrotus are succulent.
The Rounded Noon-flowers have blooms to 5 cm (2”) diameter and produce attractive floral displays that are helped by being produced for most of the year, although prolonged hot/dry conditions, or wet/cold ones will curtail this activity. Nevertheless, it is an exceptionally hardy species and despite environmental conditions will rarely succumb because of the reserve of moisture held in the leaves, although they will change color from green in good times, to an orange/red during long dry summers.
Update September 2013
Two photos added and two removed.