Lithops species are probably amongst the most well camouflaged
and cryptic plants in the world. Their common name, stone plant,
is particularly apt, as they are often extremely difficult spot
when they are growing nested amongst the gravel in their natural
habitat. They are bizarre little plants that have a strange but
fascinating beauty in their coloration and form that captures the
attention of anyone who stumbles across them. Their ease of growth
make them popular potplants and if well cared for, will make lifelong
plants consist of two fused leaves that form one head. Some species
only ever have one head, like L. gracilidelineata, whereas
other species such as L. olivacea can form big mounds of
many heads with time. From ground level, the leaves taper down to
a small, thin, carroty taproot that produces small adventitious
roots when water is available. The size of one head ranges from
5-25 mm wide and from leaf surface to root tip, from 50-100 mm,
depending on age. The windows of L. olivacea are completely
clear, as in the picture, or they are lightly spotted with grayish
flecks. L. olivacea bears a lovely yellow flower with a white
centre late in the summer.
Lithops occurs sporadically throughout all arid parts of the summer
rainfall areas of South Africa and Namibia. The two varieties of
L. olivacea, var. olivacea and var. nebrownii are
restricted to Bushmanland, however, and are found most abundantly
in the region of Aggeneys, Pofadder and Namies, although there are
earlier collections far to the east from the Kakamas area, where
it has not been seen in recent years. It is suspected that they
may have been wiped out there due to the large-scale grape farming
which has taken place.
Derivation of name and historical facts
The name Lithops is derived from the Greek lithos,
a stone and ops, a face. L. olivacea was so named
by Bolus in 1929 because of the olive green coloration of the epidermis.
The first Lithops was "discovered" by Burchell
in 1811 when he found what was at that time called Mesembryanthemum
turbiniforme from the Prieska area.
L. olivacea is a quartz lover and will always be found growing
either on big outcrops of quartz or more commonly on quartz plains
(vlaktes) where the quartz pebbles protect the plants from the blazing
summer sun by reflecting a lot of the light and heat. Another succulent
plant that is almost always found growing with L. olivacea
is Avonia papyraceae, which loves the quartz too. When it
is very dry, the plants shrivel and are almost invisible as they
get covered with fine wind-blown sand. After rain, however, they
absorb water and become fat and turgid.
Growing Lithops olivacea
Lithops plants, contrary to popular belief, are easy to grow. The
small seeds can be sown in pots of fine, well-drained sand, any
time during the summer months when temperatures are warm. Cover
the seeds with a very fine layer of grit and water from below with
a fungicide to prevent damping off. For the first 3-4 days cover
the pots with a sheet of glass/clear perspex to keep the humidity
levels high. Remove the glass and replace it with light shadecloth
and mist once or twice a day for the next two weeks after which
most seeds should have germinated. From then on mistings can be
reduced to every second and then every third day as the little plants
grow. At this stage it is not a good idea to flood the pot as this
encourages lithops soup!
When the plants are a year old, water them once every two weeks
in summer and once every 2 months (if necessary) in winter. When
the new leaves are pushing though the old leaves, watering should
be stopped altogether otherwise leaf pairs start stacking on top
of each other. They need a bright spot to grow - somewhere that
gets at least half a day of direct sunlight, otherwise they elongate
and become ugly. Mealy bug is their worst enemy - if the 'white
fluff' is found between the leaves, spray with an insecticide that
has either Chlorpyrifos or Imidacloprid as an active ingredient.
They do not need any fertilizer, but a weak solution from time to
time won't do them any harm. If well loved and cared for they make
lovely and fascinating pot plants.
- Cole, D.T. 1988. Lithops, flowering stones. Acorn Books,
- Hammer, S. 1999. Lithops, treasures of the veld. British
Cactus and Succulent Society.
- Nel, G.C. 1946. Lithops. University Press, Stellenbosch.
- Sprechman, D.L. 1970. Lithops. Associated University
Press, New Jersey.