This species has a number of uncommon features, making it easy to recognise – once you know what to look for.
It is a small shrub up to 15 cm tall of which the short shoots are decked out with small spine-like projections and it has boat-shaped leaves to 1 cm long and 0.5 cm wide (those on upper shoots are more or less round). The leaves are covered with papillae which are more or less cobblestone-shaped, but much longer on the edges.
The flowers are solitary, pinkish-purple to almost white and to about 3 cm in diameter; they appear in July-September and are followed by fruits with 6 (instead of the usual 5) compartments.
The plants occur in deep soil usually covered with quartz pebbles, from Namaqualand to Clanwilliam.
Among all the various growth forms in the genus Euphorbia, the design of this species stands out as something singular.
The plants consist of a thick main stem covered with numerous branches up to 8 cm long, decreasing in length towards the top of the plant.
In this way, a compact cone is formed up to 60 cm tall and to 25 cm across at base. In some cases however, the plants are not shaped quite so neatly, resulting in a far less appealing and peculiar habit of growth (see pictures).
The spines are in fact sterile flower stalks; they are 0.8 to 7 cm long and arise from both main stem and branches.
The species occurs on stony slopes and flats from Steinkopf in Namaqualand to the western Little Karoo.
Here the trunk is only to about 1 m tall and to 50 cm in diameter, conical to irregularly pyramidal, with silver-grey bark.
The branches are hairless, often strongly zig-zag and frequently terminating in a sharp spine; the leaves are 1.5-3.6 cm long with 3-4 (sometimes 5) pairs of leaflets which sometimes touch each other.
The flowers are yellowish-green.
The species has a limited distribution around Toliara, at altitudes from sea level to 500 m, growing in dry thickets on limestone. It is known from only 5 localities and considered endangered. This situation is exacerbated by collection of wild plants.
This species was only described in 1995 and before that time was usually misnamed O. decaryi.
Operculicarya consists of 5 species of deciduous shrubs or small trees with conical or irregularly swollen trunks, warty-bumpy bark and gnarled branches. The genus is endemic to Madagascar and belongs to the Anacardiaceae, a family of over 800 species mainly occurring in the tropics and subtropics, including well known crop plants such as pistachio, cashew nut and mango.
O. decaryi is the most widespread of the genus and occurs in dry forests in the southwest and south of the island.
It can be a small shrub or a tree, up to 6 m or more tall, with tuber-like roots*. The trunk may be parallel-sided, bottle-shaped or conical, is up to 1 m in diameter and has silver-grey or dark grey bark.
The twigs are slender, more or less straight to strongly zig-zag; young ones sometimes hairy. The leaves are 2.5-6 cm long with 4-9 (usually 5-7) pairs of leaflets, which do not touch each other.
The bright to dark red flowers are either male or female.
Like O. pachypus, the plants are becoming increasingly rare in the wild and are listed in Appendix II of CITES.
Once you know that monile is the Latin word for a string of pearls and monilaria means a collection of strings of pearl, this repetitive tongue twister of a name may begin to make more sense.
But let’s forget about the name and look at the plants themselves.
The branches consist of flattish, rounded segments and may become up to 20 cm tall.
The flowers are to 4.5 cm in diameter, usually white (sometimes with a yellow tinge), with white, orange or purple filaments*.
They have a long stalk (to 10 cm tall), appear in July-August and are highly scented.
As a rule the plants grow fully exposed in loamy soil on quartz patches in the southernmost part of the Knersvlakte.
According to “MESEMBS OF THE WORLD”, Monilaria plants are very long-lived, possibly centuries.
* the thread-like part of the stamen
All pictures shown here were taken late July 2017.