Lithops

N.E.Br.
Family : Mesembryanthemaceae
Common names : living stones, stone plants (Eng.); beeskloutjies, perdeklou (Afr.)

Lithops in flower

Lithops are one of the most popular of all the succulents. These cheeky fat little succulents plants have been grown for decades by amateur and professional succulent lovers alike.

Description
Lithops are dwarf mimicry succulent plants comprising two, thick, fleshy, semi-translucent leaves (they mimic stones). These leaves fuse together at soil level where they taper down to a single carrot-like structure which eventually becomes the root. The flattened top part of the leaf (apice) is window-like. This window performs a very important function, allowing light to enter the plant body where the sun's rays activate cells which assist with the photosynthesis process. The upper surface of the plants are of a varied and translucent nature: some have speckled lines, are grooved, or even spotted. Lithops plants come in a variety of patterns and colours.

Lithops optica

When the plant starts to flower, the bud emerges through a groove in the middle of the fissure. The fissure is the spilt between the two leaves. Flowering time is generally during the months of March, April and May (southern hemisphere). Flowers are solitary and are borne on a short stem. All lithops are noonday flowering plants. Basically this means they only flower when the sun is shining and from about 12 noon. Flower colours are white and yellow. Rarely are orange flowers produced.

Seeds are produced during the months of November and December (southern hemisphere). In most cases the seed capsules are 5- or 6-segmented. In nature the seed capsule opens when it rains and seed are dispersed by raindrops. The seed capsules are thus referred to as hydrochastic capsules (open when wet). Seeds are very small and can vary in colour.

Distribution
Lithops species have a very wide distribution. They occur mainly in the western, drier areas of South Africa . However, they are known to occur just outside Johannesburg and even in parts of the central Free State . Lithops species are also found in Namibia; one species even occurs on top of the Brandberg in central western Namibia! They are true survivors, tolerating extreme heat (above 42°C), and relatively low winter temperatures of -5°C.

The plants appear to have a wide tolerance of growing habitats, growing in quartzite pebble pavements, on dry, stony slopes or flats, calcrete soils and even in open patches in grassveld.

Lithops can under ideal conditions live for about 50 years in cultivation. In the wild the original parent plants probably don't live much longer than 25 years.

Derivation of name and historical aspects

Lithops is derived from the Greek lithos meaning stone-like or stone appearance. Hence the common name, living stones!

Ecology
Pollination is often done by bumble bee-like insects, mainly in the afternoon and early evening. It is possible that moths may also contribute to the pollination process, especially the late afternoon.

Another interesting phenomena is during extreme droughts, lithops plants can pull themselves into the soil to such an extent that they actually become semi-subterranean! In this way they are not exposed to the harsh outside elements that could dry them out even further.

Uses and cultural aspects

Some species of lithops have been collected by herbalists, especially those growing close to metropolitan areas. Some lithops are eaten just as a source of food while others are used for medicinal reasons.

Growing Lithops

Lithops plants are easily cultivated from seed and also grown by means of cuttings. Seeds are produced in November and December of each year (southern hemisphere). The seed must be completely dry. Normally the seed capsules are pale brown in colour when they are ripe. To extract the seed, merely break open the seed capsule with your fingers. The fine seed can be decantered into a small envelope. The seeds are brown in colour and are very small.

The most effective manner to sow seed is to use a well-drained substrate. Coarse s ieved river sand (1 mm in diameter) can be used. It is not necessary to cover the seed with anything. The reason for this is that the seeds are very fine and any topping or layer of soil over the seeds is likely to hamper their development. Just keep the substrate moist to stop germinating seedlings from drying out.

The ideal time to sow the lithops seeds is during the months of March, April or May in South Africa . This is the normal time that seeds would germinate in the wild, especially those from the western parts of South Africa . The seeds germinate relatively quickly. In just under a year they are ready for transplanting. Use a well-drained substrate to plant the young seedlings in. One may also decorate around the plants with quartzite stones, thus enhancing their natural appearance. Water young seedlings four times a week during hot weather. A watering of once a week during winter should suffice. Whilst the seed is germinating, use a very fine mister when watering. Any spray head that produces large water droplets will wash the seed away.

Lithops can be grown from cuttings. One must be very careful to remove all dead tissue away from the base (root). Strike the cuttings during warm weather in coarse sand. The ideal time for preparing the cuttings is in March, April, September or October. Under warm conditions the cuttings root quickly.

Reference

  • Germishuizen, G., Meyer, N.L., Steenkamp, Y. & Keith, M. (eds) 2006. A Checklist of South African plants. Southern African Botanical Diversity Network Report No. 41. SABONET, Pretoria.
  • Cole, T.D. 1988. Lithops, flowering gems. Acorn Books, Randburg , South Africa .

 

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Author

Ian Oliver
Karoo Desert National Botanical Gardens
July 2005

 

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This page forms part of the South African National Biodiversity Institute's plant information website www.plantzafrica.com

 

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