Othonna carnosa

Since its publication in 2000, “Cape plants” by J. Manning & P. Goldblattt   has been one of my main sources of information on plants of southwestern South Africa. In 2012 a new edition was published, with the somewhat unwieldy title “Plants of the Greater Cape Floristic Region 1: The Core Cape Flora”. At the same time a companion volume appeared covering the flora of Namaqualand-southern Namibia and the western Karoo, called “Plants of the Greater Cape Floristic Region 2: The Extra Cape Flora”, edited by D. A. Snyman.
I acquired this set recently and am enjoying the great amount of new information.
One of the first things I did was looking at slides of plants I have not been able to identify yet and, as expected, this has already produced some ID’s. A peculiar thing I found out is that, where a species is mentioned in both volumes, the info is not always consistent. The subject of this blog is a case in point.
When identifying plants of the genus Othonna, one of the most important questions is whether the flower heads are disciform or radiate.
In the first case, all the little flowers in the flower head look more or less the same; in the second case, the flowers along the margin of the head resemble normal petals.
The visual information below is probably slightly easier to absorb:
the flower head on the left (Othonna filicaulis) is disciform; the one on the right (O. protecta) is radiate.

When I went through the text in my new acquisition, to see if I could identify the following pictures, I came across the name Othonna carnosa with the following info:
“Succulent shrublet with short, erect or sprawling branches, 10-30 cm. Leaves fleshy, ovoid to fusiform (egg- to spindle-shaped FN).  Flower heads radiate, few in lax, terminal cymes on slender peduncles, yellow or white. Flowering mainly April-October. Sandstone slopes and stony   flats. ”
Strangely enough, when I checked the description in Volume 2, some of the information appeared to be different: “Flower heads solitary , disciform , yellow.”
The first two pictures below were taken at the same place, with a few minutes in between. As you can see, in the first picture the flower heads are solitary, and in the second the peduncles are divided.
The disciform/radiate and yellow/white questions still remain to be answered, but I am now convinced that the following pictures show O. carnosa.

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Othonna taraxacoides

Almost two years ago I published a post on Othonna auriculifolia. Today’s subject could be considered the northern counterpart of that species. Both were described in the first half of the 19th century, when taxonomy was still a very European science. This probably explains why both specific epithets refer to well known European plants: taraxacoides means looking like a Taraxacum (dandelion) and auriculifolia means with leaves like Primula auricula (bear’s ears or cow slip).

O. taraxacoides is a stemless tuberous geophyte up to 10 cm tall. The leaves are leathery and wedge- to egg-shaped or more or less kidney-shaped. Usually they are 2-3 cm long and up to 2 cm wide, with small rounded teeth and often incised with 3-5 rounded lobes.
The flower heads are 0.8-1.5 cm in diameter and appear in July and August.
The plants occur on open pebbly places or quartz patches from the
Richtersveld to Kamieskroon.

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Caralluma foetida

When not in flower, this species is difficult to distinguish from related species like C. retrospiciens and C. speciosa.
The stems are 2-3.5 cm thick and up to 20 cm tall, forming cushions to 1.5 m in diameter. The inflorescences are terminal heads of about 30 to 40 flowers, each about 2.5 cm in diameter.

The species occurs from Karamoja in Uganda and adjacent areas in Kenya to as far east as Archers Post.
Pictures were made near South Horr, Kenya, late September 2015.

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Caralluma foetida

When not in flower, this species is difficult to distinguish from related species like C. retrospiciens and C. speciosa.
The stems are 2-3.5 cm thick and up to 20 cm tall, forming cushions to 1.5 m in diameter. The inflorescences are terminal heads of about 30 to 40 flowers, each about 2.5 cm in diameter.

The species occurs from Karamoja in Uganda and adjacent areas in Kenya to as far east as Archers Post.
Pictures were made near South Horr, Kenya, late September 2015.

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Hoodia (Trichocaulon) alstonii

Of the small-flowered Hoodias this is by far the tallest, with plants growing into many-stemmed shrubs up to slightly over a meter tall and 0.5 m wide.
The stems have an unusual whitish, grey-green colour and their 20-22 obtuse angles are armed with exceptionally hard and sharp spines.
The upper parts of the stems produce large numbers of flowers 1-1.8 cm in diameter.
The species has an unusual distribution. It occurs in the winter rainfall area of
Namibia on stony hillsides east of Luederitz and along the lower reaches of the Orange River.
In South Africa it also occurs along the lower Orange River: the western part of the area here receives rainfall in winter, whereas in the eastern part the rain falls in summer.
These habitats are surprisingly arid and in general the plants grow in the open on either rocky slopes or stony, flat areas.

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Mesembryanthemum digitatum ssp. digitatum (part 1 of 2)

In my preceding post (https://enjoysucculents.wordpress.com/2015/11/01/conophytum-khamiesbergense/)  I asked the readers’ opinion on the slide scans used there.
A big thank you to all who were kind enough to respond to that request (and I’m quite chuffed because all responses were positive). Being able to mix pictures that were taken digitally with ones that were scanned, gives me a lot more options for posts.

Today’s subject with its bizarre finger-and-thumb-like leaves is certainly one of the more peculiar succulents. One cannot help but feeling that some of this otherness is reflected in its taxonomic history:
The taxon* was described in 1789 as a Mesembryanthemum, in 1925  it was placed in a genus of its own (Dactylopsis) and in 1995 it was incorporated in Phyllobolus (only to be returned to Dactylopsis in 2006). In 2013 it was reinstated -together with many other species- as a member of Mesembryanthemum.

* Taxon is a term to refer to a taxonomic group or unit of any rank (a family, a variety or whatever -depending on the context).

The plants form clumps 10-20 cm tall and are heteromorphous  (of variable shape): the first leaf of a growing period is long and the second short, giving the appearance of a “finger and thumb”.
They flower at the beginning of the resting period (November-December); the flowers stay open day and night for 3 weeks or even longer.
To see the plants in the wild, you have to go to the Vredendal/Vanrhynsdorp area of the Knersvlakte in Namaqualand, where they occur on shale covered with quartz pebbles.

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