The genus name is derived from Greek trix = hair and diadema = crown. This refers to the tuft of stiff hairs or bristles present on the tips of leaves and sepals.
The diadem is believed to be able to absorb dew and rain water. This idea is supported by the fact that in cultivation, where there is usually much more water available to the plants, the diadem is often not well developed.
The crown of hairs can be removed as a whole and is the most characteristic property of the genus. In spite of this, diadems are not present in all species, nor do they all look the same. In most cases the diadem consists of radiating hairs, but in a few species the diadem is a tuft of erect bristles. T. mirabile is a case in point.
The species forms an erect shrublet up to 8 cm tall. The beautiful, pure white flowers are up to 4 cm in diameter and appear from October to January.
The plants can be found on stony slopes from the Laingsburg area to Uitenhage.
It is easy to see why this species is so popular in cultivation. The plants are compact (the most compact of the whole genus) and have thick fleshy roots.
The diadems at the tips of the leaves are the largest of all Trichodiademas and the flowers (appearing in winter and spring: June- October) are 4-5 cm in diameter.
One can come across the plants from Uniondale to Willowmore and the southern Great Karoo, where they mainly grow in white quartz fields.
The last picture shows a plant in cultivation (scan from slide)
We often refer to scientific names in biology as Latin names, because most of them are either derived from that language or are latinised from other languages. If that were the case here too, the second part of the name should be attonsa. The name Trichodiadema is however derived from Greek (thrix = hair and diadema = crown) and because diadema is a neuter word, the second part of the name has to be attonsum.
As the name implies, most species of Trichodiadema have a crown of hairs at the top of the leaves. The word attonsum means shaved or pruned and is quite appropriate, because this species lacks the diadema that is so characteristic for most other members of the genus.
According to the literature the species occurs on rocky outcrops, as shown in the first two pictures, taken on the Rooiberg near Calitzdorp (23 Oct. 2009).
The third picture was taken 2 days ago, near the southwestern border of Anysberg Nature Reserve. Although the plant clearly does not grow on an outcrop of any kind, there are quartz pebbles present.