The Vygies of Verloren Valei

Colloquially known in English as Ice Plants, two genera from this family exist on Verloren Valei.

By Gerrit van Ede

Delosperma sutherlandii (Photograph: Gerrit van Ede)

Ice Plants—or vygies, as most South Africans and, apparently, many New Zealanders, would call them—form part of the scientific family Aizoacea, also known as Mesembryanthemaceae—a gobstopper of a word that is frequently shortened to “mesembs”.

Mesembs occur in many parts of the world, but the epicentre is the South-western Cape with more than 2000 species, or 95% of the known species. Many of them feature in the famous flower displays in Namaqualand.

The two genera that occur on Verloren Valei are Khadia and Delosperma.

The name vygie means “small fig”, and refers to the fruiting capsule, which resembles the true fig, but why the common name for the family in English is Ice Plants is not so clear to me (another common name is carpet weed). Apparently, it is because the leaves are covered with flat or rounded glistening epidermal bladder cells or other structures that glitter, reminding somebody of ice crystals. These bladder cells are water storage structures that the plants deploy to survive the hot dry summers in the Karoo. They may also help in keeping the plant temperature down and the name Ice Plant may also have been given because the plants feel cool even in hot summer weather.

The species most mentioned in this respect is Mesembryanthemum crystallinum. This species (and some of the others) is highly salt tolerant, thanks in large part to the bladder cells.

The name Mesembryanthemum is derived from the Greek, mesēmbria (noon) and anthemon (flower) because the flowers only open at midday. They, in fact, normally only open in bright sunlight and when it is warm. Anybody that has visited Namaqualand to look at the flowers knows that you need warm sunny days to see the flowers. This also applies to the vygies and not only to the annuals.

In addition, though, there are however night-flowering mesembs.

Another characteristic of the mesembs is the fruiting body or capsule, the “little fig” from which its Afrikaans name comes. The capsules tend to be woody, and have compartments called locules, which open when wet and close or partially close again when it gets dry. This characteristic is dubbed hydrochastic in the scientific literature. These capsules and the number of locules and how they behave in wet and dry weather is used as identifying characteristic of a species.

The genus Delosperma

The genus Delosperma contains about 170 species. In contrast to most vygies, they mainly come from the summer rainfall area of Southern Africa (162 species). Since the genus was first described in 1925 by N. E. Brown, no systematic classification has taken place although I am aware of work taking place on this genus now.

Identification of the different species of Delosperma is not that easy. We think three species occur on Verloren Valei with Delosperma sutherlandii the most often seen in various places on Verloren Valei and forming even scattered colonies.

Colony of Delosperma sutherlandii on Verloren Valei (Photograph: Gerrit van Ede)

The name Delosperma is derived from the Greek delos meaning conspicuous and sperma meaning seed. This clearly refers to the seed capsules that are very conspicuous on the plants as with virtually all mesembs.

Delosperma sutherlandii with seed (Photograph: Gerrit van Ede)

Delosperma sutherlandii has the largest flowers of the genus, being up to 60mm in diameter. This species, as well as many other species in the genus, are good garden plants in South Africa. They are summer growing, relatively drought resistant and can handle cold well. D. sutherlandii is light to dark pink in colour. I have seen no white forms. Most of the bladder cells are converted to glistening hairs as can be seen in the photo.

D. sutherlandii occurs in the grasslands at Verloren Valei in many areas. They occur among rocks, in open grassland, on slopes as well as relative flat areas. Therefore this species can adapt to a number of localities on the reserve.

This species is not threatened and indicated as of Least Concern in the Red Data Book of Plants

The genus Khadia

Only six species exist within the genus Khadia, which is restricted to the summer rainfall area in South Africa, mainly the northern provinces.

Khadia alticola—the most common pink colour (Photograph: Gerrit van Ede)

In the past the fibrous roots of this genus was added to alcoholic fermentations, known as khadi, to make them more potent—hence the name. Khadi are made by fermenting various indigenous fruits that occur in the area where the plants grow. In the more northern, warmer areas of South Africa, the Marula fruit (Sclerocarya caffra) is used, while in colder areas, fruit obtained from three Grewia species (G. flava (Brandybush), G. occidentalis(Cross-berry) and G. flavescens (Rough-leaved raisin) are alternatives. Today the drink is seldom made.

Khadias grow in shallow soil over rock and have, except for one species(K. borealis), thick fibrous roots. They mainly occur above 1400m above sea-level. Again except for one species (K. media), they grow on sedimentary derived soil.

K.alticola, as its name indicates, occurs at high altitude—the Steenkampsberg Mountains are a good place to find them, they are however not that common on Verloren Valei. In suitable places with shallow soil on rock, K. alticola forms quite large colonies and, when in flower, the mass of flowers is quite impressive.

The flowers of K.alticola are fairly large, up to 50mm in diameter, and are basically in shades of pink. White forms do also occur.

The rarer white-flowered K. alticola (Photograph: Gerrit van Ede)

The plants make attractive rockery subjects, forming low, dense clumps with showy flowers.

The capsules of the genus Khadia are made up of a varying number of locules (compartments). In the case of Khadia alticola, the plant has six locules, which open when wet, but do not close completely when they get dry again.

Khadia alticola is considered as Rare in the Red Data system.

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