Lithops ... 1/3

Introduction

Lithops grow in Southern African especially the western area. They are a member of the Mesembryantheum or Aizoaceae family. They are very popular, but can be difficult to grow for the novice.
"Lithos" means stone in Greek, and "ops" means like, so lithops literally translates as "stone like".

In their natural habitat they grow in very dry areas with just the top of the leaves being visible with it's intricate pattern of lines and spots, possibly mimicking the surrounding stones and soil (hence the common name "living stones") this may mean that animals do not see them as they seek out food.
In fact when Lithops where first discovered by man their second subsequent discovery did not happen for a couple of years later, even though the searchers knew the plants were there!, many a searcher has literally walked over the plant/s as they searched for them. Also being buried in the ground means water loss is reduced in the hot dry environment.

In cultivation Lithops are grown with the leave/s out of the soil in most cases (or at least the upper layer consisting of stones or grit) because we cannot reproduce the high temperatures and low humidity of it's natural habitat, and grown habitat-like in cultivation would make them more prone to rot.

I like to think Lithops grow in autumn/winter and rest in summer, but you water them in spring/autumn and leave them dry in summer/winter ... this is because in autumn the plant is flowering and in winter a new pair of leaves (or even a twin pair of leaves) is growing, obtaining their moisture from the old leaves until in spring/summer there is left a paper-thin shell of old leaves with a new lush pair of leaves underneath. Think of the snake shedding it's old skin as it outgrows it.

Internal Structure

Photos (courtesy of Roy from the BCSS forum) showing the two thick succulent leaves - consisting of the translucent patterned window at the top, along the sides or inner layer of the epidermis are the chloroplasts receiving the light filtering down from the top after it has passed through water storage cells - which weakens the ultra strong desert sunlight. As a cone-shaped light collector when the sun is directly overhead LESS sunlight hits the chloroplats while the weaker early morning/late afternoon sunlight have less water cells to move through before reaching the chloroplasts. As a further adaption there is little or no stem, before the roots start, as a stem is not necessary to survive.

This photo was taken late winter, and shows the next years body leaves (2 pairs in this case at a right-angle to current year, as the lithops is starting to clump) forming at the bottom, a seed capsule still maturing from the previous summer going up between the two pairs of leaves. At this stage last years plant is still quite turgid and hasn't shrivelled much yet.

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