306 MAINTENANCE OF A FREE PASSAGE FOR AQUEOUS VAPOUR. 



moors which border the Baltic Sea, and in the cold Arctic tundra. This shrubby 

 evergreen vegetation of the Cape belongs indeed in part to the same families as 

 these. Heaths especially are to be found in abundant variety; as many as 400 

 species can be counted — main- more than are furnished by the whole of the rest of 

 the world taken together. But a great number of species from other families, viz. 

 Rhanmeae, Proteacere, Epacridea?, and Santalaceae, possess an exactly similar foliage, 

 and without blossom and fruit are often indistinguishable from the heaths. This low 

 evergreen bush vegetation is not distributed all over the Cape, but is restricted to 

 the neighbourhood of the coast, to the country which slopes in terraces down to the 

 south-west, and to the celebrated Table Mountain, rising abruptly above Cape Town. 

 The aqueous vapour brought by the sea-winds condenses directly over these regions, 

 and for five months, from May till the beginning of October, the soil is not only 

 soaked by abundant rain, but what is perhaps of even greater moment, all the ever- 

 green bushes are kept in a damp condition by the falling mist, and often are 

 dripping with water just like the heaths on the moors of the Baltic lowlands. 

 When the development of vegetation on the lower terraces of the south-west coast 

 is at a standstill on account of the increasing dryness, the summit of the Table 

 Mountain is still enveloped in the celebrated mass of cloud known as the "table- 

 cloth ", and the plants growing on the ridges and plateaus are during this time as 

 much saturated as the Trailing Azalea, which robs the south wind of its moisture on 

 the mountain ridges of the Central Alps. It is, however, in this damp period that 

 the growth of the plants in question takes place. Most of the plants on the heights 

 of the Table Mountain blossom and put forth new shoots in February, March, and 

 April; on the lower terraces from May to September. In the northern regions and 

 on mountain heights the beginning and end of the year's work in plants is limited 

 by the cold, but in the Cape the dryness of the soil is the cause which brings the 

 upward current of the sap in vegetation to a standstill for so long a time. At the 

 coast, however, this dryness is never so severe that the plants are exposed to the 

 danger of withering up altogether, as on the steppes. 



As on the south-west coasts of the Cape, so is it round about the Mediterranean 

 Sea and in the west of Europe, which is swept by sea-winds laden with vapour 

 fi-om the Atlantic; for example, Portugal and the south-west of France, which are 

 in like case, characterized by an abundance of low bushes, with evergreen rolled 

 leaves, and especially by some gregarious heaths. Here also the year's growth 

 takes place in the wettest season, and arrangements must be made that during this 

 period the formation of organic materials, the withdrawal of food-salts from the 

 soil, and consequent^ 7 unhindered transpiration may be carried on. Here, too, dry- 

 ness interrupts the activity of the absorbent roots, and the evergreen vegetation of 

 the coast-line extends inland as far as the damp sea-winds make themselves felt; 

 while still further inland a steppe-like vegetation preponderates. The analogy pre- 

 sented by the Mediterranean flora goes so far that, on the southern point of Istria, 

 for example, which may be compared as to shape with the south point of Africa, 

 quantities of the evergreen Erica arborea are onry to be found on the south-west 



