In the spring, in those years when rain has fallen, for two months the Karoo is a flower garden. As far as the eye can reach, stretch blots of white and yellow and purple fig flowers;[6] every foot of Karoo sand is broken open by small flowering lilies and waxflowers; in a space a few feet square you may sometimes gather fifty kinds of flowers. In the crevices of the rocks little flowering plants are growing. At the end of two months it is over; the bulbs have died back into the ground by millions, the fig blossoms are withered, the Karoo assumes the red and brown tints which it wears for all the rest of the year. [6] Fig = Mesembryanthemum. Sometimes there is no spring. At intervals of a few years great droughts occur, when for thirteen months the sky is cloudless. The Karoo bushes drop their leaves and are dry withered stalks, the fountains fail, and the dams are floored with dry baked mud, which splits up into little squares; the sheep and goats die by hundreds, and the Karoo is a desert. It is to provide for these long rainless periods that all plant-life in the Karoo is modified. Nothing that cannot retain some form of life habitually for six months, and at need for eighteen months, without rain, can subsist here. The Karoo bush, itself a tiny plant a few inches high, provides against droughts by roots of enormous length stretching under the ground to a depth of thirty feet. At the end of a ten months' drought, when the earth is baked into brickdust for two feet from the surface, if you break the dried stalk of a Karoo bush you will find running down its centre a tiny thread of pale-green tinted tissue still alive with sap. Some plants maintain life by means of fleshy bulbs buried deep under ground, and in years when no rain falls they do not appear above the surface at all. Many plants have thick, fleshy leaves, in which they store up moisture against the time of need; some, such as the common sorrel and dandelion, become ice-plants; all over their fleshy leaves and stems are little diamond-like drops, which when broken are found to be full of pure water, a little plant sometimes having half a cupful stored in this way. Some have their leaves closely pressed together into little solid squares or balls, so saving all evaporation from their surfaces. Many are air plants; and, fastened by the slenderest roots to the ground or rocks, live almost entirely on the moisture they may draw from the air, and will grow and bloom for months or even years in a dwelling without either earth or water.