384 



THE SEA SHORE 



characterised by a cylindrical, cartilaginous, unbranched frond, 

 with scattered, naked spores. A very small species (L. pusillus) 

 with tufted green fronds grows parasitic on the fronds of Chorda 

 and the stems of Laminaria. It is only two or three inches long, 

 has a reticulated surface, and is covered with minute jointed fibres. 

 A still smaller species (L. laminarice), seldom exceeding half an 

 inch in length, forms brown tufts on Alaria, and the rounded apex 

 of its frond is covered with minute fibres. 



The order Laminariacecz contains olive, inarticulate algfe, 

 mostly of large size, and generally growing in deep water beyond 

 the tide-marks. Their spores are superficial, either covering 

 the whole surface of the frond or collected into indefinite cloudy 

 patches. 



The typical genus (Laminaria) is characterised by flat leathery, 

 ribless fronds, either simple or cleft, and supported on a stem 

 which is often very thick and strong. The old laminae fall off every 

 year, and are replaced by new fronds. The well-known Tangle 

 or Sea Girdle (L. digitata), is a very common species on the rocks 

 just beyond low-water mark. It has a very thick, solid, cylindri- 

 cal stem, and an oblong leathery 

 frond which is entire when young 

 but deeply cleft later. Small 

 specimens may be found just 

 above low-water mark, but fine 

 large ones are commonly washed 



FIG. 268. Laminaria bulbosa FIG. 269. Laminaria saccnarina 



up on the beach. Although this weed may not be regarded as an 

 acquisition from the collector's point of view, it will generally repay 

 a careful examination, as it frequently bears rare parasitic species. 

 The other common species are the Furbelows (L. bulbosa), known 

 by its flat stem with waved margin, oblong frond cleft into narrow 

 strips, and the hollow bulb or tuber just above the root ; and the 



