The photos in this post were originally published here as belonging to O. undulosa, but Derek Tribble of London kindly made me aware of them representing in fact O. gymnodiscus. For more information see Derek’s comment.
This is a tuberous, erect or sprawling plant to 35 cm tall, with leathery, oblanceolate to elliptic leaves which are tapering below and somewhat clasping.
The solitary yellow flowerheads are terminal or axillary and disciform ((without ray florets); they appear in July and August.
Its area of distribution is from Cedarberg to Worcester and Little Karoo to as far east as Port Elizabeth on sandy slopes and flats.
Taxonomy
Avonia used to be a subgenus of Anacampseros, a relatively small genus in the family of purslanes (Portulacaceae).
The species within the genus Anacampseros consist of small to very small shrublets with a more or less thick, sometimes branched stem. The fleshy leaves form a flat rosette or are attached to the stem in a spiral. A typical characteristic are the stipules (lateral outgrowths at the base of the leafstalks). Often these have been reduced to hairs, or grown into parchment-like white scales which in some species can completely cover the stem including the real leaves. In 1994 Gordon Rowley concluded that these species with scale-shaped stipules deserve the status of a separate genus; thus the genus Avonia came into existence. In it, he placed 9 species. There are now 12. The name is probably derived from the Latin ‘Avus’ which means grandfather. It would then refer to the white scales that give the plants an ‘old’ appearance. Rowley placed a few other Anacampseros-like plants in the genus Grahamia. According to his classification, 15 species remain in the genus Anacampseros.
Together, the genera Anacampseros, Avonia, and Grahamia form the branch (tribe) Anacampseroteae within the Portulacaceae.
Incidentally, it is doubtful whether the genus Avonia will hold. It is rather unusual today to base a genus on a similarity in its external appearance. As a rule, the characteristics of the flower and seed and even more so the similarities and differences in DNA play a decisive role.
Flower and fruit
What all representatives of the Anacampseroteae have in common is the construction of flowers and fruit. The flowers, which in all species are only open for a few hours in the late afternoon, always have only 2 sepals, which first completely enclose the flower and often curl up after flowering but remain joined at the tip so that they stay on top of the developing fruit like a cap. This can be seen very well in Avonia quinaria ssp. alstonii (fig.1). At a certain moment the cap falls off and the seeds are released.
Fig. 1
Furthermore, there are usually 5 (sometimes 4) petals , which are white, pink or carmine. The stamens are white with yellow anthers and very variable in number: from 5 in, for example, Anacampseros comptonii to as much as 80 in A. quinaria (fig. 2). The white pistil has 3 lobes. The fruit consists of a kind of veined basket that often has a narrow opening at the top, so that the seeds come out in dribs and drabs as if with a salt-sprinkler as the flower stem bends to the ground and is moved up and down by the wind.
fig. 2
A. papyracea was chosen as the type species of the genus because of its most pronounced characteristics. The name papyracea (=paper-like) is particularly appropriate because a stem looks like a little wad of wafer-thin pieces of paper. The name was given by the German botanist and director of the botanical garden in Königsberg, Ernst Heinrich Friedrich Meyer (1791-1858). The description under the taxonomic rules followed a bit later and is by the Austrian botanist Eduard Fenzl. It appeared in 1840 in a large article about the Molluginaceae (which at that time still included the Portulacaceae) in ‘Annalen des Wiener Museums der Naturgeschichte’. Hence the designation ‘E. Meyer ex Fenzl as found in botanical literature.
The white scales undoubtedly protect the green leaves underneath them against the bright sunlight. Rowley observed that under humid conditions the scales deflect somewhat from the stem so that there can be a better exchange of gases (oxygen, water vapor) with the environment. Perhaps water can also be absorbed in liquid form.
Like most Avonias, A. papyracea hails from South Africa (Western and Northern Cape). It is fairly common and grows mainly in plains with white quartz stones. But the plant also grows on dark coloured soil, where it is of course much more obvious. Figure 3, a photograph by Coby Keizer, shows a cluster in Goegap Nature Reserve east of Springbok.
The former director of the Royal Botanic Gardens at Kew, Sir William T. Thiselton–Dyer, pointed out that the white stems bear a certain resemblance to bird droppings. It is not for nothing that the plant is also called ‘gansmis’ (goose dung) in South Africa. Probably the geese have a different menu there than in Europe, because here the droppings of geese are just as green as the grass they eat. Thiselton–Dyer suggested that this is a mimicry plant, which in this way tries to prevent it from being seen as a tasty snack. If that is the case, then it does not seem to be a successful imitation, because another name for the plant is ‘haasieskos’ (Hare food). The same name is also used for A. ustulata and A. filamentosa. Thiselton-Dyer made his remark in 1906 in an article in the British ‘Annals of Botany’. At that time, the flower was still completely unknown. In the same article he mentions that his friend Nicholas Edward Brown, also from Kew, had been growing the plant for many months, but despite daily observation had never seen a flower on it. Yet, suddenly a fruit appeared from between the parchment-like leaves. He concluded that the flower had to be very small and hidden under the scales had fertilized itself. A cleistogamous species, in other words. Later authors also maintain that the flowers do not open. But that’s not true. Sometimes the plant does bloom and the flowers are not small nor do they remain hidden under the scales (Fig. 4).
Thiselton-Dyer also reported in the article mentioned above that the stalk of the ripening fruit continues to grow so that the seeds are scattered at some distance from the mother plant. This can also be clearly seen in Fig. 4.
Fig. 4. The flower of A. papyracea and a seed pod.
However, this is not always the case. In Fig. 5 it can be seen that the 2 fruits hardly appear from between the scales.
Fig. 5. A full seed pod of A. papyracea and an already emptied one. Both only just visible between the scales.
In addition to the usual species which is nowadays referred to as A. papyracea ssp. papyracea, there is also a subspecies: A. papyracea ssp. namaensis. This occurs in the northwestern part of South Africa and in the south of Namibia and is distinguished by the fact that the scales are not smooth-edged but serrated (saw-edged) or toothed and by the seeds that are lumpy. In ssp. papyracea they are more prickly (Fig. 6).
Fig. 6. The seeds of A. papyracea are slightly prickly.
Seed collection is extremely simple. Holding an empty tube or something similar under a ripe fruit and a tap against the fruit are enough. Immediate sowing gives excellent results. At a temperature of 25 to 30 °C, the seedlings emerge en masse after a week. Only a short time later, the seedlings proceed to develop the papery scales (Fig. 7).
Fig. 7
A year later they have become miniatures of the mature plants ( see fig 8).
Fig. 8
Cultivation
I grow the plants in standard cactus soil and I also treat them like cacti. This means that they receive water regularly in summer and that I keep them dry in winter. I try to keep the temperature in my greenhouse around 8 °C in winter, but it sometimes drops to just above freezing point. According to the literature, even temperatures of 5 degrees below zero are survived.
Apparently, A .papyracea, like A. ustulata, was also used in South Africa as a kind of yeast for baking bread and making beer. To this end, roots and stems are dried and ground. It is suspected that the plant also contains psychoactive substances, just as, by the way, A. quinaria. The brew must have been a kind of ‘spacebeer’.
Literature
Browne, P. (1756). The Civil and Natural History of Jamaica. In Three Parts [3]: 234
Fenzl, E. (1840). Monographie der Mollugeneen, Annalen des Wiener Museums der Naturgeschichte, [2]: 295
Marloth, R (1917). Dictionary of The Common Names of Plants, The Specialty Press of South Africa, Ltd. Cape Town
Rowley, G. (1994). Anacampseros and allied genera- A reassessment, Bradleya 12: 105-112
Sims, J. (1811) Anacampseros filamentosa, Curtis’s Botanical Magazine 33: plate 1367
Thiselton-Dyer, W.T.(1906). Morphological Notes, Annals of Botany 20 (2) blz 123-127
Originally published in Succulenta 93: 2014. Translated from Dutch by FN.
This species is a common sight on soft saline soil and low outcrops in the Richtersveld, from north of Lekkersing to the Augrabiesberg, at an altitude of 200-300 m. This is a winter rainfall area, which receives less than 100 mm rain per year.
It develops large, dense clumps 6-10 cm tall and up to 50 cm in diameter.
The more or less erect leaves are pale greyish white to bluish green, broad and thick (1-2.5 cm) and up to 4.5 cm long.
The flowers are 5-6 cm in diameter and range from cream and yellow to orange-red, sometimes with a purplish tinge. They appear in winter and spring (August-September).
This attractive species is widespread in the summer rainfall area of South Africa from the North-eastern Karoo into the Free State and Bushmanland and is also found in southern Namibia. It occurs in flats, in shale or coarser sand or gravel and easily establishes itself along roadsides and in other open spaces.
The plants are rather variable: compact to freely branched with creeping branches, forming dense mats or growing in tufts.
The leaves are more or less trigonous, 1-2.5 cm long, 0.4-0.5 cm wide and thick; they are covered with prominent whitish warts.
Flowers appear from August to December; they have a very short stalk and are about 1.5 cm in diameter. The petals are golden yellow but reddened at the tip on the back surface. They open from late afternoon to early evening.
NB. The picture labelled C. musculinum in Robin Frandsen’s “Succulents of Southern Africa” does not show this species but rather a Stomatium.
Succulent fanciers usually are not impressed by Haworthia flowers. On a wispy stalk there are a number of insignificant, mostly dirty white flowers. In H. truncata, the flowers have brownish longitudinal stripes. How different things become when you look at one of those flowers in close-up (fig. 1).
Fig. 1 Close-up of a flower of Haworthia truncata
The petals end in gracefully curly transparent slips and the ensemble is reminiscent of a majestic flying swan.
In nature the pollination of the tubular flowers is often done by bee species with extra-long mouthparts. Honey suckers (the African counterpart of the hummingbird) also play a role in pollination.
Fig. 2 The plate accompanying the description by Schönland in Transactions of the Royal Society of South Africa (1910).
Haworthia truncata was found in April 1909 by a certain Miss L. Britten on a farm 7 miles from the town of Oudtshoorn in the Little Karoo (Western Cape, South Africa). In 1910, the description by botanist Selmar Schönland appeared in the South African magazine ‘Transactions of the Royal Society of South Africa’. The accompanying plate shows the plant with detailed drawings of the various parts (see fig. 2).
Fig. 2 The plate accompanying the description by Schönland in Transactions of the Royal Society of South Africa (1910).
The formal description is followed by Schönland’s reflection on the morphology and anatomy of this special plant.
Karl von Poellnitz distinguished three forms of H. truncata in 1938: fa. normalis, fa. crassa with thicker and less flat leaves and fa. tenuis which remains much smaller. The latter was described as a variety by M.B. Bayer in 1976.
According to current taxonomic insights, these different names are unjustified and one name is sufficient for all the varieties and forms mentioned: H. truncata subsp. truncata. The closely related H. maughanii is seen as another subspecies: H. truncata subsp. maughanii.
Haworthia truncata is an outsider among the Haworthias. To begin with, the species differs from the standard Haworthia in that the leaves are not arranged in a rosette but are aligned (see fig. 3).
Fig. 3 Seedling of Haworthia truncata (Vanwykskraal) in cultivation.
In addition, the leaves, which are almost completely hidden in the ground, are flattened at the top (but with some differences in height) and all at about the same level so that it looks like they have been cut off with a blunt knife just above the ground (truncata means shortened). The cross-section is almost rectangular, so that the whole plant (sideways) is reminiscent of a fan or a multi-armed candlestick. The upright truncated leaves have earned the plant the name ‘Perdetande‘ (Horse Teeth) in South Africa. In Schönland’s drawing (fig. 2) the leaves do not have that typically rectangular shape, but are more similar to the leaves of H. maughanii.
To prevent the growing plant from protruding above the ground, there is another special faculty. The roots have transverse grooves that allow them to contract and thus bring down the plant body. Pretty much like an earthworm can contract.
Schönland explains that the plant, of which only the top of the leaves is visible, looks like a collection of pebbles and therefore does not stand out. In other words: it is a mimicry plant that in this way tries to protect itself from being eaten by animals. In order to receive enough light for assimilation, the leaf surface is somewhat transparent so that the light can penetrate to the assimilating tissue located on the inside of the leaf. This means that H. truncata can be counted among the so-called window plants, which we find mainly in the mesems. Think of Fenestraria, Frithia and several Lithops and Conophytum species. Schönland believes that this type of Southern African plant species that grow in full sun should in fact physiologically be considered to be shade plants.
In South Africa, they use different wording for all this.
In the question and answer section ‘Vra vir Ernst’ of a South African newspaper, I found the following description of H. truncata by Ernst van Jaarsveld:
‟In nature, the Horse Teeth are found in the Klein Karoo, especially in the Oudtshoorn district. They grow partly under bushes in stony conglomerate soil. Only the blunt leaf tips stick out of the ground, like horse teeth. They are difficult to spot and adapted to the arid environment. The leaves like those of beeskloutjies (little cow hoofs = Lithops spp.) are translucent green. In times of drought, the leaves shrink, and the dust covers the plants until they are almost invisible to humans.”
Haworthia truncata remained rare in European collections for quite some time after its discovery in 1909. In the Dutch monthly magazine ‘Succulenta’ it was first written about only in 1932 by the then widely known G.D. Duursma:
“Haworthia truncata Schönl. is a welcome addition of recent years, predestined to become so popular that it will soon be present in many collections.”
Cultivating the species is not particularly difficult. In South Africa, the plant grows and flowers in the rainy season. That’s in September and October. It makes sense to maintain this growing period in the northern hemisphere as well. This means that the plant should receive as much light as possible in these months and be watered regularly. In our climate, growth usually takes place in spring too. In the summer months, shade should be provided in the heat of the day and just enough water should be given to prevent the plant from drying out. The pot should not be too large, because then the soil may remain wet for too long after watering, resulting in rot. In literature it is reported several times that the roots periodically die and that the plant then quickly makes new roots in fresh soil. Like all plants of the Western Cape, the species is not sensitive to cold.
As a rough estimate, H. truncata grows at less than 10 localities in the vicinity of Oudtshoorn and west of it near Calitzdorp. Well-known locations are Dysselsdorp and De Rust, both east of Oudshoorn.
Fig. 4 Haworthia truncata near Dysseldorp (photo Coby Keizer).
Fig. 4 shows a group on a flat hilltop west of Dysselsdorp. The plants there occur generally in full sun but sometimes also under bushes. The soil is sandy and mixed with large and small stones.
Other succulents Coby has seen there are Cotyledon orbiculata, Aloe humilis and Aloe humilis hybrid (humilis x microstigma), Anacampseros arachnoides, Crassula capitella ssp.thyrsiflora, Crassula subacaulis, Duvalia species, Quaqua spec., Stapelia spec, Gasteria spec, various mesems and caudiciform plants. A true paradise for succulent fanciers.
Between Dysselsdorp and Kammanassie Dam (about 10 km to the south), a small variation occurs in which the leaf edges usually have small, pointed protrusions reminiscent of hairs. This form was described by German Ingo Breuer as var. minor (fig. 5, photo Robert Wellens). Later on, Breuer elevated this variety to a separate species: H. papillaris.
Fig. 5 Haworthia truncata var. minor VA 6718 (photo Robert Wellens).
At Van Wykskraal, about 5 km from Dysselsdorp, a natural hybrid with H. arachnoidea seems to grow.
The populations have suffered severely from the collecting frenzy of succulent lovers and traders. In addition, there is habitat destruction due to increasing urbanization of the area. On the Red List of endangered South African plants, the species has been given the status ‘vulnerable’.
In addition to the natural hybrids, there are countless artificial ones, often with variegated leaves or different folds of the leaf surface. Worth mentioning is the hybrid “Lime Green” (fig. 6, photo Robert Wellens), probably a cross with H. cuspidata, although H. cymbiformis is also considered to be a possible parent.
Fig. 6 Haworthia ‟Lime Green” (photo Robert Wellens).
Of H. maughanii (fig. 7-9) only one locality, south of Calitzdorp, is known. The area is less than 1 km2. Here too, a lot of damage has been done by succulent hunters and there is also damage from ostriches trampling the plants. All this has led to the status of ‘Critically Endangered’ for this species. The habitat of this species partly overlaps with that of the form of H. truncata which was described as fa. crassa and there are all kinds of natural hybrids in this area.
Fig. 7 A seedling of Haworthia maughanii (H. truncata ssp. maughanii) in cultivation.Fig. 8 Haw. truncata v. maughanii in habitat. Photo Frans Noltee
| Fig. 9 Haw. truncata v. maughanii in habitat. Photo Frans Noltee
Literature:
–Duursma, G.D. (1932) Haworthia truncata, Succulenta 14 (7): 169-172.
–Jaarsveld, E. van (2001). Vra vir Ernst, Lastige molkrieke en die biologiese bekamping van plae, Die Burger, Kultuurkroniek, http://152.111.1.87/argief/berigte/dieburger/2001/09/08/4/19.html
–Schönland, S. (1910). On some points in the morphology and biology of a new species of Haworthia, Transactions of the Royal Society of South Africa 1 (2): 391-394.
–Red list of South African Plants, http://redlist.sanbi.org/genus.php?genus=2215
First published in Succulenta 93, 2014-2. Translated from Dutch by Frans Noltee.
This species produces firm creeping stems up to over 60 cm long.
The leaves vary from narrowly elongate to egg-shaped and are flatly triangular in cross-section, grey green, up to 2 cm long and 0.6 cm wide. The basal leaves are erect and larger.
From September to December the plants display their pale pink or white, sometimes yellow, flowers, which are up to 3.5 cm across.
The species occurs from Namaqualand to the dry regions of the winter rainfall area of the Western Cape and is rather common on flats and among rocks and abundant as a pioneer in disturbed places such as roadsides.
C. cotyledonis is very widespread and displays a great variation in size and shape of the leaves (even within the same population).
The plants form a basal rosette and usually only a few branches up to about 20 cm tall. The leaves are broadly lance-shaped to broadly egg-shaped (narrower in the Karoo) and flattened but somewhat convex above and below; they are grey-green to yellowish green, 3 – 6 (-9) cm long and 1-2.5 (-3.5) cm wide, densely covered with coarse recurved hairs (a good way to recognize the species). On the margins the hairs are longer.
The tube-shaped flowers are cream to pale yellow and appear from September to January; they are arranged in dense round clusters.
Occurring from southwestern Namibia to the Little Karoo and the Eastern Cape; usually on gravelly slopes and outcrops among rocks and bushes.
C. robusta has a wide distribution which is probably the cause of its considerable variation in certain features. This in turn has led to a high number of synonyms (16 in total).
It is easy to cultivate and to flower, one of the reasons for it being probably the most common species of Cheiridopsis in cultivation.
The plants form loose clumps, 20 cm tall and up to 40 cm across.
Their leaves are mucronate*, 5-8 cm long and about 1.5 cm thick; triangular in cross-section, pale greyish blue to greyish green with a reddish tinge and decorated with translucent spots.
Flowers are 6 cm in diameter, cream to yellow to white , often with pink, purple or orange tinges; they appear in August-September.
C. robusta is very common in the Richtersveld and also occurs in Southern Namibia, both winter rainfall areas with less than 100 mm rain per year. It is mostly found on rocky/gravelly flats or slopes, below 600 m in altitude.
These are compact plants (spissum = dense, close together), up to 10 cm tall and up to 15 cm in diameter. They have dark green leaves which are 4.5-7 cm long and triangular to slightly round in cross-section.
The beautiful flowers have stalks to 5 cm long and are nearly 4 cm across. Compared to most other Cephalophyllums, they are rather subdued in colour (purple to salmon-pink, with a paler centre); they appear in July-August.
The plants are often confused with C. caespitosum but they have fruits with 11-15 instead of 9-10 compartments.
They occur in the southern Knersvlakte in loamy soil among white quartz pebbles; often together with Argyroderma delaetii.
Crassula expansa is a very variable species which is widespread from southern Namibia to Tanzania and Madagascar. There are 4 subspecies, of which ssp. expansa is the most common.
This is a short-lived plant with soft and usually creeping branches, forming mats to 6 cm tall and 50 cm across.
The branches are green to reddish, and rooting at the nodes. Its leaves have a wedge-shaped base and a sharp tip; they are 6-12 mm long and 4-6 mm wide, inversely egg-shaped to almost linear, with a flat upper surface and a convex lower surface, or rarely almost round in cross-section; they are yellowish green to brown (or red when plants flower) with a reddish margin and often shiny.
The small (about 3 mm in diameter) cup-shaped flowers are white, often tinged red and appear mainly in July-December, but also at other times, especially after occasional rains.
Plants are found in KwaZulu Natal and in the Northern, Eastern and Western Cape Provinces, often on rocky or sandy slopes and sometimes abundant in disturbed places.
fig. 2
Fig. 6. The seeds of A. papyracea are slightly prickly.
Fig. 7
