THE MARINE BOTANIST. 201 



tion : ly external ttibercles, containing dense clusters 

 of spores (favellidia) ; 2, tetraspores scattered 

 through the surface of the frond. 



GIGARTINA MAMILLOSA— WARTY 

 GIGARTINA. 



Fronds from three to six inches high, forked, the 

 segments wedge-shaped, stem channelled. Tuber- 

 cles borne on small processes, in great numbers, on 

 the surface of the upper segments, giving them the 

 appearance of being covered with small warts. 

 Colour a dark purple. Substance tough and carti- 

 laginous. Grows on rocks, stones, in pools near 

 low water-mark. Common. Perennial. Autumn 

 and Winter. 



0. S. G. pistillata. Grow on rocks, near low 

 water-mark. Very rare. Perennial. Spring. 

 Coast of Cornwall, in several places. Whitsand 

 Bay, near Plymouth. Mount Bay. Padstow. 

 Jersey. Fronds from three to six inches long, 

 narrow, compressed, forked -, when in fruit the upper 



