THALLOPHYTA 17 



Among the Brown Algae an example of this kind is the genus Splachnidium 

 (Plate 2, Fig. B) which is not only confined to the rocky coasts of the southern 

 seas, but is also the only known representative of its family. The general 

 appearance of the plant is well shown in the figure, a characteristic feature 

 being the very slender base of the axis and its branches. The dots on the 

 surface mark the position of flask-shaped cavities called concefttacles. 

 Each of these is lined by a number of hairs, most of which project through 

 the apex of the cavity ; among them are several club-shaped bodies called 

 Sporangia,-, each of which contains numerous zoospores. These are set 

 free, come to rest, and grow into new Splachnidium plants. The growth 

 of the axis is controlled by means of a very remarkable apical cell, quite 

 unlike any other apical cell known in the plant kingdom. It is found in 

 the centre of a small depression in the somewhat flattened apex (Fig. 12). 

 The central part of the plant is made up of branched filaments embedded 

 in mucilage. 



Another characteristic Cape sea-weed is the large Ecklonia buccinalis* or 

 sea-bamboo, from the basal part of which fish horns t are often made. This 

 basal part is cylindrical and hollow, often three or four feet long, very tough, 

 and attached to the rocks by means of irregularly-branched hold-fasts. It 

 terminates above in a large frond, split almost to the base into a number 

 of linear segments. At the junction of stalk and frond a few smaller segments 

 occur, on the smooth surface of which certain slightly raised areas are found. 

 These mark the position of the reproductive organs, which cover the raised 

 portion of the thallus and consist of club-shaped sporangia very similar to 

 those already met with in Splachnidium. 



X. RHODOPHYCEAE. 



The Red Algae. 



While the Brown Algae are conspicuous for their size the red forms are 

 remarkable for their beauty. They are all fairly small, although the thallus 

 may show considerable complexity, and nearly all are marine, growing at or 

 below low water. A very few of the simplest red algae, however, grow in 

 fresh water. 



Amongst the Red Algae one of the most characteristic South African 

 genera is Cheilosporum. This is a small, fan-shaped, pale strawberry- 

 coloured plant, generally growing in rather dense tufts on the rocks, at or 

 just above low water mark. The plant is illustrated in Plate 2, Fig. L. Like 

 other members of the family, Coral Algae, is is somewhat thickly incrusted 



* Named after Christian Friedrich Ecklon, an apothecary, who came to the 

 Cape in 1823. Fired with enthusiasm for botany, he gave up his profession and made 

 large collections of plants in various parts of South Africa. 



■f The drivers of carts offering fish for sale in the streets of Capetown and other ports 

 blow these horns in order to make their presence known. 



