RHODOPHYTA OF TROPICAL AFRICA 75 



Note. Doubt attaches to the placement of this species in the genus Erythrotrichia due to the 

 reported release of the entire contents of the cell as a spore (Dangeard, 1 1), and the development 

 of new plants from small cells loosened from the penetrating basal rhizoids. Ardre (4) has pointed 

 out the close resemblance of this species to Bangia whilst Heerebout (24) has preferred to retain 

 it in Erythrotrichia rather 'than to erect a new monotypic, closely related genus for it'. Branching 

 in this species may be the result of in situ spore germination, as has been reported in E. carnea 

 (Dixon & West, 1967). 



Erythrotrichia sp. 

 Senegal (50). 



Bangiaceae 



Bangia atropurpurea (Roth) C. Ag. 



Nigeria (unpublished). 



[As Bangia fuscopurpurea (Dillw.) Lyngb.j 



Benin (30). 



Gabon (31). 



Ghana (29). 



Senegal (12; 29; 37; 50; 51). 



[As Bangia fusco-purpurea Lyngb.] 



Canaries (9). 



'. . . De la Norvege aux Canaries . . .' (9). 



Note. For the conspecificity of marine and freshwater species, see Geesink (1973). 



Porphyra 



There is a curious absence of Porphyra from the Gulf of Guinea and adjacent islands. The 

 genus is represented in Senegal and further north, and is present from southern Angola south- 

 wards. The single exception, from Cameroun, that highlights this discontinuity is the collection 

 described by Pilger (45); it is certainly in the genus Porphyra. The extent and depth of recent 

 studies in the Gulf of Guinea indicate that Porphyra is probably not being overlooked. 



Porphyra capensis Kiitz. 



South West Africa (17; 43; 44; 47; 49). 



[As Porphyra sp.] 



Angola (39). 



Note. Material previously attributed by us only to genus has been kindly specifically deter- 

 mined by Miss J. Graves. 



Overall note. Several Porphyra species were reported from southern Africa in the nineteenth 

 century. J. Agardh (1883) recognized just one, retaining the name P. capensis for a whole plexus 

 of forms previously named, inter alia, P. umbilicalis. See Isaac (1957) and Graves (1969) for 

 general autecological data. 



Porphyra ledermannii Pilger 

 Cameroun (15; 37; 45). 



Note. Conway et al. (1976) recognize seven criteria as important to delimitation of species in 

 Porphyra; these relate to the macroscopic thallus. Pilger (45) gave data for only three of these 

 criteria (gross morphology, structure, habitat) and on present grounds P. ledermannii hardly 

 warrants separate recognition since the material was also sterile. The original material of P. 

 ledermannii is certainly a Porphyra species; it is now in such a state that specific attribution is not 

 possible. De Toni (15), who had no authentic material from which to judge, suggested some 

 affinity with 'Porphyra carnea Grun.' from Madeira. Porphyra carnea is little known; it probably 

 relates to P. umbilicalis (see Piccone, 1884 : 51). 



