FLORA OF SOUTH AFRICA. 10« the current loses little by evaporation, and often holds out till the middle of summer. The water is also frequently dammed up and thus retained in its bod for several weeks and even months together by the thousand little barriers formed by the den^e masses of s<:>dge growing at certain points along the banks of the stream. The discharge is thus regulated by the aquatic vegetation so / effectually that these river valle^s are entirely free from the sudden freshets, which in a few hours often convert the wild mountain torrents of Abyssinia into liquid avalanches. Although flourishing in a temperate climate corresponding to that of West Europe, the flora of the Cape presents u remarkable contrast to the analogous forms of the northern hemisphere. Its jwricxl of repose coincides, not with the cold but with the hot season, so that the expression "to hibernate" is here quite inapplicable. The deciduous plants lose their foliage in the dry |jeriod extending from March to May, but when rain begins to fall the temperature is still suffi- ciently high, even during the cold season, for the vegetation to revive, put forth its leaves and blossom. Even the plants introduced from other countries have acquired th'- same habits. According to M. Bolus, they comprise altogether about one hundred and sixtv species, and are mostly of European origin, but also include some from America and India. These exotics are seldom met at any great distance from the high- ways and European settlements. In the interior they are scarcely ever seen, and on the whole they cannot be said to have hitherto exercised any marked influence on the South African vegetable world. The indigenous species have sf> far success- fully resisted the foreign intruders, and, it left to themselves, would probably in course of time recover all their lost ground. Two plants alone of the northern latitudes have found in Austral Africa a perfectly congenial climate and suitable soil. These are the liarbarv fig, which is spreading over the less fertile tracts, and the Pin us pinea, which is gradually encroaching on many rocky slopes. The species introduced int« the Cape from Europe are nearly all ornamental |,'lants; they are reckoned by the hundred, and they form the pride of the conservatories adaptt^d for the cultiution of sjM?ciniens belonging to the temperate zones of the earth. Miiny of the towns in the south- western districts are already encircled by fine avenues of oak-trees. At the end of the last and beginning of the present century the indigenous species were held most in favour, and fashion had enthroned them the queens of every garden. As early as the middle of the seventeenth century, that is, before the country was colonised, passing seafarers had already brought specimens from the Cape of Gocd Hope to the Dutch florists. In the direction of Algoa Hay the character of the vegetation becon;es gradu- ally modified along the seaboard districts. Here the varieties peculiar to the Capo disappear and become replaced by those belonging to the East African coastlands. Only a few ferns still straggle on, and the geraniums almost cease to le represented, for here begins the mariiiir.e /one of the Indian (keiin. where the climate is at once warmer and more humid than on the shores of the Atlantic. A few tnpical
