Cystopteris diaphana (Bory) Blasdell.

Fischer, Eberhard & Lobin, Wolfram, 2024, Checklist of Lycopodiopsida (clubmosses and quillworts) and Polypodiopsida (ferns) of Rwanda, Willdenowia 53 (3), pp. 149-172 : 160

Cystopteris diaphana (Bory) Blasdell.

First recorded — Brause & Hieronymus (1910: 2) mentioned Cystopteris fragilis auct. non (L.) Bernh., but this was overlooked by recent researchers (e.g. Roux 2009).

Note — Cystopteris diaphana [= C. viridula (Desv.) Desv. ] according to Lobin (1986), is distinguished by the veins ending in sinuses between the teeth (vs ending in apices of teeth in C. fragilis ) and the spiny-lacunar spores, so densely covered with spines that they obscure the surface (vs echinate spores loosely covered with spines in C. fragilis ) ( Fig. 1, 2). He recorded the species for the Canary Islands.

Fraser-Jenkins (1986) made the first record for the African mainland ( Cameroon). A description of C. viridula with comparison to C. fragilis is also provid- ed by Murphy & Rumsey (2005). Verdcourt (2003: 5) distinguished two subspecies of C. fragilis . His “subspecies B” exactly matches the key characters of C. diaphana . Roux (2009) followed Verdcourt’s taxonomic view (2003) and listed “subspecies B” from Algeria, Morocco, Cameroon, Sudan, Ethiopia, Uganda, Kenya, Lesotho and South Africa. All records probably belong to C. diaphana but need verification by spore characters. According to Roux (2009), this species is known only from the Comoro Islands and Réunion. The author also erroneously placed C. viridula as a synonym of C. fragilis . Here we provide the first definite record of C. diaphana for Central Africa.