OF NORTHUMBERLAND AND DURHAM. 307 



On rocks above half-tide level. Not very common. Whit- 

 burn, Roker, Hawthorn, &c. — G. S. B, Berwick. — Dr. John- 

 ston. — N. D. 



/3. PURPUREUM. 



Byssus purpurea. E. Bot , t. 192. 

 A stunted variety, which spreads extensively over rocks in 

 the form of a dense purple crust. It occurs generally near high- 

 water mark, and is more common than the typical form of the 

 plant. Seaham, Roker, Marsden, &c. — G. S. B. 



9. C. FLORiDULUM, Ag. Harv. Man., p. 183. Phyc. Brit., t. 



120 (A). Atlas, PI. LIX., fig. 277. Johnst. 

 and Cr., vol. ii., p. 195. 

 On shelving sand-covered rocks at extreme low-water mark. 

 Roker and Whitley. — G. S. B. My Whitley specimen of this 

 plant bears numerous bodies, apparently antheridia, ai ranged like 

 tetraspores in a secund manner on the ultimate ramuli. This 

 species seems to be of rare occurrence in England. — N. D. 



10. C. SPARSUM, Harv. Harv. Man., p. 184. Phyc. Brit., t. 



297. Atlas, PI. LX., fig. 280. Johnst. and 

 Cr., vol. ii.,p. 199. 

 On Cladopliora rupestris at Roker. — G. S. B. — 13 . 



11. C. Daviesii, Lyngl). Harv. Man., p. 184. Phyc. Brit., 



t. 314. Atlas, PL LX., fig. 281. Johnst. and 

 ^Cr., vol. ii., p. 201. 

 Conf. Daviesii. E. Bot., 2329. 

 Parasitical on the smaller Algaj, particularly on Callithamnion 

 Hookeri and on Polysiplionioe. — N. D. 



12. C. viRGATULUM, Harv. Harv. Phyc. Brit., t. 313. Atlas, 



PI. LX., fig. 282. 

 Parasitic on Polysiplionia nigrescens^ &c. Probably a variety 

 of the preceding. — N. I). 



