100 COMMON SEAWEEDS. 



liarly a northern seaweed. Those who explore the 

 tide-pools of Scotland, north of Ireland, and coasts 

 of Durham and Northumberland, may find it abun- 

 dantly, and it is well worth collecting. 



Generic character. — A flat frond, toothed at the 

 edge, dark red or purple, faintly ribbed ; from three 

 to twelve inches long. 



Fructification. — Twofold on distinct plants. 1. Ce- 

 ramidia more open at the pore than those of the Poly- 

 siplionia, vase-like, containing a cluster of pear-shaped 

 spores. 2. Stichidia in long pods, containing a 

 double row of tetraspores. 



The fruit is found on the margin of the frond, or in 

 the axils of the teeth, on delicate pellucid stalks. 



NACCAKIA WIGGHII. 



(Named after Naccaki, an Italian botanist.) 



A most charming plant, and very rare ; but Miss 

 Theodora Clarke found it at Shanklin, Isle of Wight. 

 In Jersey Miss "White and Miss Turner find it, and 

 in Guernsey it is also found at extreme low tide. 



Generic character. — Frond flat, rosy red, from six 

 to twelve inches high, with irregular branches beset 

 with minute ramuli, which become swollen with fruit, 

 and then resemble pods of rich crimson hue, filled 

 with spores. 



When examined under a microscope, the structure 

 of this plant is beautiful : the centre of the stem is 

 occupied by large transparent cells, over which is 

 spread a covering of minute cells, and the frond has 

 the appearance of rose-coloured net- work. 



