OLIVE SEA- WEEDS. 103 



remainder of the Melanosperms, including the Sphace- 

 larice and Ectocarpi, are plants of small size, filamentous 

 and much-branched, and form bunches or tufts, growing 

 for the most part on other plants. Thus, most of the 

 Fuel and Laminarieoe become covered, as the season ad- 

 vances, with small parasites belonging to these families : 

 and others grow on the smaller Algse in tide-pools. 

 Several are objects of much beauty. 



With a short account of the Red Sea- weed or Rho- 

 dosperms I shall conclude this hasty sketch of the 

 various tribes of Algce. The Red Sea-weeds are by far 

 the most numerous in species, the most beautiful in 

 form and colour, and the most perfect or elaborate 

 in structure of all the class of Algae. They also 

 characterise a greater depth of water. Many of them 

 grow beyond the influence of the tide, and can only 

 be procured by the dredge, except when a strong gale 

 loosens them from their position, and throws them up 

 on the beach. The majority grow close to low-water- 

 mark, and are to be seen only for an hour or two at the 

 spring-tides : so that a person visiting the shore at neap- 

 tides may leave it ignorant of half its treasures. The 

 favourite locality of the more delicate Floridece (as the 

 Rhodosperms are frequently called) is on the perpendi- 

 cular sides of deep tide-pools under the shade of larger 

 plants. In such places, either Fucus serrahis orHiman- 

 thalia lorea commonly grows on the top of the rocky 

 margin, while the fronds rest on the surface of the 

 water. On removing the Fuel a host of delicately-beau- 

 tiful Floridece will often be revealed. This is the usual 

 position of the various species of Griffithsia, some of the 



