370 THE SEA SHORE 



the former prevailing in the deep and shady pools and the depth 

 of tint decreasing according to the amount of exposure to the 

 bleaching action of the sun. 



A second species (C. squamata) is very similar in growth and 

 habit, but is much less common, and is confined to the neighbour- 

 hood of low-water mark. It may be distinguished from the last by 

 the form of the segments, which are short and globose in the lower 

 portions of the stem, and become broader and more flattened 

 towards the tips of the branches. 



Another genus Jania contains a few coralline weeds that 

 are somewhat like Corallina, but are of a more slender habit and 

 smaller, and have a moss-like appearance. They may be distin- 

 guished by the forked branching of the slender frond, and by the 

 position of the conceptacles in the axils of the branches, and not at 

 the tips. J. rubens is a very common red species that grows in 

 tufts on other weeds. It has cylindrical segments, longer towards 

 the tips of the branches ; while another and less common one 

 (J. corniculata], found principally on the south coasts, has flat- 

 tened segments except in the branchlets. 



A third genus of the order Melobesia contains a very 

 peculiar group of algae that would certainly never be regarded 

 as plants by those who did not know them. They are apparently 

 mere solid incrustations of calcareous matter, without any jointed 

 structure, and often of very irregular form, covering the surfaces of 

 rocks, shells, or weeds. They are of varying colours, some pre- 

 vailing tints being dark purple, lilac, rose, and yellow ; and they 

 are equally variable in form, some being decidedly lichen-like, 

 some resembling fungoid masses, and others consisting of super- 

 imposed leaf-like layers. They are not weeds to be pressed for 

 the collector's album, but require storing in boxes or trays like sea 

 shells. As in the case of the branched corallines, the hidden 

 vegetable structure may be revealed by dissolving away the car- 

 bonate of lime ; and the spore-conceptacles, with terminal pores, 

 may be seen scattered irregularly over the surface. 



The order Laurenciacecs contains some beautiful pink, red, and 

 purple weeds with round or flattened branching fronds. They 

 may be known by the disposition of the tetraspores, which are 

 irregularly scattered over the branches; and by the pear-shaped 

 spores in rounded capsules. The typical genus (Laurencia) in- 

 cludes an abundant weed (L. pinnatifidd) which was formerly 

 eaten in parts of Scotland, where it is known as the Pepper Dulse 



