Marine Alyce of Berwick-on- Tweed. 287 



Plants which, bear plurilocular sporangia differ slightly from 

 those with unilocular fruit. 



In specimens with plurilocular sporangia the surface of 

 the frond is smooth, blackish-green, waved, sometimes tubercular 

 or bullate in the centre. These plants retain their orbicular 

 form for a long time, and fronds six or even eight inches in 

 diameter still orbicular in outline are sometimes to be met with. 

 In the plants which bear the unilocular sporangia, on the other 

 hand, the surface of the fronds is very rough, reddish-brown, 

 and always more or less bullate. The older fronds are, more- 

 over, very irregular in outline. 



Dr. Johnston* sent specimens of this species, from Berwick, 

 to Dr. Grreville, who wrote concerning them, " Zonaria deusta \ 

 has a reddish colour which your plant has not, and a corrugated 

 burnt appearance, which yours has in a much less degree. I 

 think that your plant may turn out to be my Padina parvula 

 (Zonaria parvula, Crypt. Fl. t. 360) in a mature state." I 

 suspect that Johnston's specimens belonged to the form bearing 

 plurilocular sporangia. 



Subgenus— STKAGULARIA, Stromfelt. 



The species belonging to this subgenus resemble Myrionemata 

 in fructification, and Lithodermata in structure. The fronds are 

 composed of a single horizontal layer, from which arise short 

 vertical filaments, loosely united to one another and easily 

 separable under pressure, not firmly united so as to form a solid 

 parenchymatous structure as in Ralfsia proper. The paraphyses 

 and spores arise from the apical cells of the vertical filaments of 

 the thallus and form indefinitely extended sori, rather uniformly 

 diffused over the frond, and lighter coloured than the barren 

 portions of it. In fact, as Dr. Farlow remarks, \ these plants 

 may be said to be Ralfsia with diffuse fructification and slightly 

 developed fronds, or Myrionemata with excessively developed 

 basal portions. 



Stromfelt, unwilling to unite the families Myrionemata and 

 Lithodermatea, makes Stragularia the type of a new family 

 Stragulariacea. 



* Flora of Berwick, vol. n., p. 248. 



f Ralfsia verrucosa, Aresh., (non Balfsia deusta J. Ag.) 



J Marine Algae of New England, p. 88. 



