382 THE SEA SHORE 



a common species, is of a pale greenish or olive colour, and very 

 soft and slimy. Its stem is round and slender, freely branched, 

 with short, simple branchlets. 



The order Diciyoiacece contains the olive weeds with inarticulate 

 fronds, and superficial spores disposed in definite lines or spots. 

 In the typical genus (Dictyota) the frond is flat and forked, some- 

 what ulva-like and ribless, and the spores are produced in little 

 superficial discs just beneath the cuticle. There is only one British 

 species D. dichotoma but that is a very common one, and it 

 assumes a great variety of forms as regards the shape and division 

 of its fronds according to the situation in which it grows, the fronds 

 being broadest and strongest in the deepest water. The root is 

 covered with woolly fibres, and the frond is regularly forked. 



One of the most interesting algae of this order is the Turkey- 

 feather Laver (Padina pavonia), which is the only British repre- 

 sentative of its genus (see Plate VII.). Its very pretty fan-shaped 

 fronds are of a leathery nature, curved, fringed along the upper 

 margin, and marked with concentric lines. They often bear small 

 leaflets, and are partially covered with a powdery substance which 

 renders them beautifully iridescent when in the water. The root 

 has woolly fibres, and the spores are arranged in lines along the 

 upper margin. This weed seems to be confined to the south coast, 

 where it may often be seen in the deeper tide pools; though in 

 some of the sandy bays of the Isle of Wight it may be seen in 

 shallow pools, and even in places left exposed to the air at 

 low tide. 



The genus Zonaria contains a British species (Z. parvula) that 

 covers the rocks in round patches ; and though moderately common 

 is not very frequently seen by collectors on account of the fact that 

 it grows in the deep crevices of rocks at or near low-water mark. 

 Its frond is flat and membranaceous, more or less divided into 

 lobes, without veins, and rather obscurely divided into concentric 

 zones. It is attached to the rock by fibres that proceed from the 

 under surface of the frond, and the spores are arranged in clusters 

 beneath the superficial cells. 



Cutleria multifida, though not very abundant, is to be found 

 on most of our coasts ; but since it grows almost exclusively beyond 

 low-water mark, it should be looked for on the beach after storms, 

 or in the fishermen's nets. The frond is olive-green, fan-shaped, 

 rather thick, and irregularly divided into forked branches ; and 

 it has a beautifully netted surface. The spore-cases may be seen 



