This member of a small group of geophytic Euphorbias has underground tubers up to 2.5 cm thick which can form large groups. The plants are stemless and either male or female.
Its leaves have a stalk up to 5 cm long and may be oblong to almost lanceolate, linear or elliptic,1 to 5 cm long and 0.5 to 2.5 cm wide, often minutely hairy and grey-green, usually with wavy margins. They are only present in the growing period.
The flowering season is mainly June-September.
The species occurs on sandy and gravelly flats and slopes from near Springbok to the Cape Peninsula and the western part of the Little Karoo.
Othonna cacalioides is a dwarf compact caudiciform with a flattened potato-like caudex, most of which is below ground. The plant body is broader than tall and to 10 cm across, covered by a tough leathery bark of a muted brownish or orangish colour.
The branches are reduced to low lumps with thickish, 2-2.5 cm long, and 0.8-1 cm wide leaves (only present in winter and spring).
From May to October, the plants produce inflorescences with 2-8 cm long stalks, each with up to six small, yellow flower heads.
Usually, the plants are found in shallow rock pans with a thin layer of coarse sand in sandstone pavements in the Northern and Western Cape (Bokkeveld Mountains to Gifberg). Sometimes they occur in patches of greyish moss. In both cases, they are often and hard to find, especially when not in leaf.
Although they are slow-growing and difficult to keep alive, this seems to make them only more attractive to collectors.
P.S.
In 2012 the Swedish botanist Bertil Nordenstam created a new genus (Crassothonna) with 13 species, formerly part of Othonna. One of these species (O. carnosa), for nomenclatural reasons, had to be renamed Crassothonna cacalioides. This has unfortunately created quite a bit of confusion because many people assume (understandably but wrongly) that this is the new name for Othonna cacalioides.
In short: Crassothonna cacalioides is what used to be called Othonna carnosa and Othonna cacalioides is still Othonna cacalioides.
Mature plants of this species usually have a globose caudex to 10 cm tall and to 9 cm in diameter. The branches are about a cm thick and normally about 1.8 cm long.
The species is very rare and only occurs between Calitzdorp and Oudtshoorn in the Little Karoo. It was described in 1999, but nowadays the consensus seems to be that it should be incorporated in E. decepta.
There is only one place in the world where this species is known to occur: Tanjona Vohimena, the southernmost tip of Madagascar*.
On this stark, wind-swept limestone terrace about 100 m above sea level, the species occupies an area of less than a km².
Old plants possess a large turnip-shaped root to 30 cm long and to 10 cm wide, topped by a densely branched crown to 30 cm in diameter. In habitat the branches creep along the ground as a result of the constant wind; in cultivation they are more or less erect.
The leaves form rosettes at the tips of the branches, they are to 25 x 8 mm in size and green to red-brown.
* The old name for this is Cap Sainte Marie, which explains the specific epithet.
In the dormant state, without leaves and flowers, this species is difficult to distinguish from P. densiflorum and P. rosulatum. They share the same habit: low, multi-branched shrubs up to 1.5 m in diameter and up to 1 m tall.
P. horombense is named after the Horombé plateau in the southern highlands of Madagascar, where it often occurs in great numbers on granite rocks.
The inflorescence has an erect peduncle of no less than 60 cm tall, with broadly cup-shaped flowers 1.7-2.3 cm in diameter.
According to Werner Rauh in his great book on the succulents of Madagascar, this is:
“the most beautiful Pachypodium species in cultivation”.
Although Mt. Ibity is perhaps the most accessible place, P. brevicaule also occurs in a couple of other habitats in Madagascars central highlands.
Plants can be found from Ambositra to Antananarivo in quartz rock at altitudes between 1400 and 1600 m.
In some spots where P. brevicaule grows together with P. densiflorum or P. rosulatum, one can come across hybrids. Judging from the long flower stalks, I suppose the plants shown in pictures # 3 and 4 belong to either of these hybrids.
The first two pictures show views from where P. brevicaule grows on Mt. Ibity. On # 2 you can see the quarry belonging to the massive cement factory nearby.
Attractive dwarf shrublets up to 15 cm tall with a caudiciform base up to 3.5 cm in diameter.
Branches are short and fat, with peeling yellow-brown bark; covered with flat white phyllopodia (leaf-bases) when young. The leaves are usually up to 4 cm long and 5-7 mm wide.
The flowers are tubular, erectly spreading to pendulous and relatively large (up to 1.8 cm long). They appear in November and December.
This species is widely distributed from southwest Namibia to the Knersvlakte, on flats and stony slopes, often with quartz rocks or pebbles.
Rainfall in the area is 100-200 mm per year, mainly in winter. The temperatures are high in summer and moderate in winter, sometimes with light frost.
Of the about 900 species of the Pumpkin Family (Cucurbitaceae), nearly 10% can be classified as a caudiciform succulent. The subject of this post is a clear example.
It is a climber with a tuberous rootstock 15-20 cm across, which is visible above ground and tapers into the stems which may be up to 7 m long.
Young stems are green and soft, soon becoming dark green, grey or brownish and somewhat woody.
The plants are dioecious (either male or female) and produce egg-shaped
fruits which are bright red, up to 7 x 3 cm and beaked (=rostrata).
The species occurs in deciduous bushland, thicket , woodland and wooded grassland from sea level to 1650 m in tropical East Africa: southern Ethiopia and the adjacent part of Somalia, northeastern Uganda, Kenya, northern and central Tanzania.
The pictures were taken in Kenya and northern Tanzania, except for the last one, which shows a young plant in cultivation.
The fact that this species is a deciduous geophyte is reflected in the name, as one of the meanings of the word resurgens is: “Rising again, as from the dead”.
The plants are only up to 3 cm tall, with a thick caudex covered in cork, short stems and
leaves with large bladder cells.
In June-September they produce greenish yellow to pale salmon, distinctly scented flowers about 4 cm in diameter.
If you want to see the plants in nature, you have to go to the Northern or Western Cape Province, where they are widespread in the winter rainfall area from Namaqualand to Ceres and Laingsburg.
I first saw plants of this species in autumn (May 2006) and had no idea what they were. Some peculiar Mesem maybe? The first picture gives you an idea of what they looked like.
It took me about half a year to return to the spot (a few km northwest of Matjiesfontein) to try and make some good pictures, but when I came there, the plants had disappeared. There were no signs of digging by man or beast and I was sure it was the right spot. So what had happened? After a while it started to dawn upon me that the only thing that was wrong was the time. Because summer was approaching, the plants had done their annual disappearing act and I would have to wait till autumn to see them again.
In March of the following year I found out that the species was rather common in the area and also that they sometimes were much more visible (see pictures below).
