76 D. M. JOHN, J. H. PRICE, C. A. MAGGS & G. W. LAWSON 



Porphyra leucosticta Thur. 



Angola (26). 



Canaries (4; 6; 18; 19; 41; 52). 



'. . . Atlantique (de la Suede aux Canaries . . .' (4). 



'. . . Atlantique nord (de la Suede aux Canaries . . .' (18). 



[As Porphyra leucosticta J. Ag.J 



Angola (25). 



Porphyra umbilicalis (L.) J. Ag. 



Canaries (42). 



Cape Verde Islands (19; 22). 



Senegal (12). 



[As Porphyra laciniata J. Ag.] 



Cape Verde Islands (5). 



'. . . Afrique meridionale . . .' (5). 



[As Porphyra laciniata C. Ag.] 



Cape Verde Islands (16). 



'Throughout the Atlantic Ocean, from the Faroe Isles to the Cape of Good Hope.' (35). 



Note. The northern records implicit in this generalized statement probably do relate to P. 

 umbilicalis; the southern records have been shown to relate to P. capensis Kiitz. (q.v.). 



[As Porphyra laciniata (Lightf.) C. Ag.] 



'Ad litora maris Atlantic! , a Scotia usque ad Caput bonae spei.' (2). 



Note. See note above. 



[As Porphyra vulgaris C. Ag.] 



'Throughout the Atlantic Ocean, from the Faroe Isles to Cape Horn . . .' (35). 



Note. See note above. 



[As Ulva laciniata (Lightf.) C. Ag. 3. umbilicata (Mohr) C. Ag.] 

 'In mari Atlantico, a Faeroeis usque ad caput bonae spei.' (1). 



Note. See note above. 



[As Wildemannia umbilicalis (L.) De Toni] 



'ad rupes in oceano Atlantico et ejus sinubus europaeis et africanis; . . .' (14). 



Note. The use of the name Porphyra umbilicalis by Kiitzing (1843 : 383) for material from 

 'Schottland' considerably antedates J. Agardh's (1883 : 66) placement in this genus of Linnaeus's 

 (1753 : 1163) Ulva umbilicalis. In making his later combination, J. Agardh gave no indication of 

 being aware of Kiitzing's earlier use of the same epithet, although this may have been a purposeful 

 act. J. Agardh is still credited with the combination in the latest version (Parke & Dixon, 1976) 

 of the British marine algal check-list, although the species is indicated as requiring nomenclatural 

 reinvestigation. The purely nomenclatural process of discarding the name P. umbilicalis on the 

 grounds that any combination of author attributions represents confusion (Kiitzing did not 

 refer to Linnaeus, and J. Agardh ignored the Kiitzing statement) is highly undesirable, especially 

 when other utilizable epithets are either undistinguished or, as for example with the P. vulgaris 

 C. Ag./P. purpurea (Roth) C. Ag. situation, of even more doubtful nomenclatural validity. 



We have therefore decided only to outline the problem and to avoid a decision that involves 

 name changing, in that none of the courses of action open to us will clarify the position. The 

 combination Porphyra umbilicalis is used and understood by all, and the biological integrity 

 of the taxon to which the name is by long custom applied is hardly in question. We trust that 

 good sense will prevail and that the unused Kiitzing name will not be allowed to disturb 

 a relatively stable situation. Even in that situation, however, there are difficulties. 



