HAWORTHIA TRUNCATA (Perdetande)

Guest column by Theo Heijnsdijk

 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

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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.

Anacampseros lanceolata

Common names: boesmansuring, hasiekos.

This clump-forming species is similar to A. telephiastrum, but up to 10 cm tall and thereby the largest member of the genus.
Its leaves are lance-shaped*, to 4 cm long and to 2 cm wide ( wider than thick), rounded below but almost flat above and ending in a minute spiny tip; they are blue-green at the beginning of the growing season, but become wrinkled and brown at flowering time. The white hairs in the leaf axils are often longer than the leaves.
The inflorescence is up to 25 cm tall, with 1 – 4 pink or white flowers, which are  to 3 cm in diameter; the petals are almost as wide as long, with a pointed tip. Flowering time is October to December.

The plants are found on rocky flats or slopes from the Richtersveld  to the western Karoo, Little Karoo and Langkloof.    Anacampserotaceae

* a shape which is broadest at about a third from the base and gradually gets narrower till it ends in an acute tip.

 

Cephalophyllum purpureo-album

Because of the epithet purpureo-album (purple-white), one would expect most -if not all- plants of the species to have purple flowers with white stamens. That may have been the case in the plant on which the original description was based, but yellow flowers with pale yellow (or white) stamens are much more common.

The plants form clumps up to 60 cm in diameter with more or less cylindrical, mostly dark green leaves, which are about 6-10 cm long and more slender than in other Cephalophyllums.
In May-September, they produce yellow or pale purple flowers up to 5 cm in diameter with 70-110 petals and up to 260 stamens. The number of compartments in the fruits is also high (13-17).

Judging from the number of synonyms (C. aurantiacum, C. gracile, C. littlewoodii, C. middlemostii, C. paucifolium, C. serratulum and C. worcesterense), the species is quite variable.
It occurs in the western Little Karoo and in the Robertson Karoo, where the plants are often locally abundant in open patches on sandy, loamy or gravelly flats.
In a suitable (Mediterranean-like) climate, the species – just as many other Cephalophyllums- will make an excellent garden plant.

 

Mesembryanthemum subtruncatum

What I find intriguing in this little annual, is the way the flowers open and rearrange their petals.
The flowers appear in October, are pink with a white or straw-coloured base and may be up to 2.5 cm in diameter.
The plants are up to 10 cm tall and 15 cm in diameter; the leaves are club-shaped, bright green but turning reddish when the flowers start appearing.

In the Tanqua Karoo and Little Karoo the species is locally abundant in disturbed places (usually in quartz).

Quaqua (Caralluma) ramosa

Because of its unusual stems, this species is normally easy to recognise.
It occurs in the Little Karoo and the southwestern Great Karoo on lower stony slopes and hilltops, usually inside or next to other bushes.
The flowers appear normally in March-May, in small clusters near the top of the purplish to greyish green stems. They emit a strong smell of buck or sheep urine.

 

Quaqua (Caralluma) mammillaris

Of all species of Quaqua, this is the one with the widest distribution and also probably the best known.
The plants form vigorous clumps of up to 60 cm tall and wide.
Even when not in flower, the plants are usually easily recognised by their size and the hard, yellow-brown spines. The flowers appear in March-June and emit a very unpleasant smell.

Occurring in a great variety of habitats from southern Namibia to Rietbron in the Great Karoo and Oudtshoorn in the Little Karoo.

Aloe longistyla (Karoo aloe, Karoo aalwyn, ramenas)

Unlike most other dwarf South African Aloes, this species is usually single, but sometimes 2 or 3 rosettes are formed and rarely even up to 10.
Each rosette consists of 20-30 greyish-green to bluish-green, waxy leaves, 12-15 cm long, with soft to hard white spines on both sides and on the margins.
The inflorescences are simple and dense, 15-25 cm tall with very thick stalks. The flowers are about 5.5 cm long (remarkably large for such a small plant) and have a very long style (=longistyla); they appear in June-August and are salmon pink to coral-red.

Usually growing in the shade of small shrubs, the plants occur on stony or sandy flats, sometimes on gentle slopes, from Laingsburg and the Little Karoo to Middelburg and Makhanda (= Grahamstown) in the Eastern Cape. Unfortunately, the plants are short-lived and don’t grow well in cultivation, not even in the area where they occur naturally.

 

 

 

Pelargonium rapaceum (Bergaartappel, Bergpatat, Norretjie)

Occurring from the northern Richtersveld to the Eastern Cape Province, this is one of the most common of the tuberous Pelargoniums and also the one with the widest distribution. It is found in a wide range of habitats, from stony slopes and flats to farmland that has been left fallow; it can even quickly colonize disturbed areas.

The tubers are often partly exposed and usually turnip-shaped (= rapaceum); usually there is only a single tuber, but sometimes a string of additional tubers is formed so that the plants can become quite large.
The  softly hairy leaves are up to 40 cm long and 4.5 cm wide.
In October – February the plants produce branching peduncles with up to 50 flowers which are about 2.5 cm in diameter, white, cream, yellow or pink and most unusual in resembling little pea-flowers.

 

 

Haworthia maraisii v. maraisii

The pictures below were made on the edge of a Eucalyptus forest a few hundred meters from my home. As is usual for them, the plants occur here on rocky outcrops, well hidden in patches of coarse sand or between stones.
They slowly form small groups of 
rosettes. Each rosette is 4 -7 cm in diameter, consisting of few to many, dark green to brown leaves which are usually flat above and rough with raised tubercles; the margins and keel are decorated with small spines.
In March- May the plants produce inflorescences up to 30 cm tall with white flowers (often with a yellow throat).


Accompanied by Adromischus filicaulis ssp. marlothii

 

 

 

 

 

 

 

 

Euphorbia colliculina (vingerpol)

Only known from 4 localities between Calitzdorp and De Rust in the Little Karoo, this species is highly endangered by habitat loss and degradation (caused by ostrich farming and quarrying as well as soil erosion and urban expansion). The situation is further exacerbated by ruthless collecting.
It is a member of the medusoid (caput-medusae) group: the plant consists of a large caudex, an underground tuber and rings of erect to spreading branches which are 3-12 cm long and to 2 cm thick.
The species is said to be close to E. fortuita occurring further west in the Ladismith area.