*-w> 







MR 



ON THE GEOGRAPHICAL DISTRIBUTION OF FERNS. 



317 



Ascension Island yields only seven species, as follows : 



Pteris incisa. 

 flabellata. 



Asplenium erectum. 

 *Nephrodium Ascensionis 



Polypodiurn trichomanoide 

 *Gymnogramma Ascensionis 

 Marattia fraxinea. 



var. purpurascens 



Two of these are peculiar, two common to Africa and America, two African only, one 

 American only ; so that it is very curious to note that, if we sum u p in a single j >hrase 

 the leading characteristic of the Pern-floras of the Atlantic islands, it is in each case 



different. 



American affinity. 



Individuality. 



The want of any decided characteristic 



Mediterranean affinity. 



Of Tristan d' Acunha, the characteristic is . 



St. Helena 



Ascension Island 



Canaries, Madeira, and Azores . 



We must note, in passing, the want of individuality in the Angolan Fern-flora. A few 

 of the Angolan ferns are Cape species which do not reach Guinea ; but the rest, with 

 the exception of six species, all occur elsewhere in this district. For the cast side of the 

 continent, principally through the explorations of Schimper in Abyssinia, and Kirk in 

 Zambesi-land, we know now 133 species ; but here there is even still less individuality 

 than in Angola— not a single peculiar species in Zambesi-land, and m Abyssinia only 



Asplenium pumilum is an east continental species only known elsewhere in Ame- 



" ~ " mm melanolepis m 



one. 



rica, Cheilanthes Kirkii in Angola, Cheilantlies arabica and Onych 

 Arabia and Persia 



Taking next 



the East African islands, including Madagascar, Mauritius Bourbon 



find that they have a Fern-flora which 



But dealing 



and the Seychelles and Comoro groups, we Una tnai wiey "».«. « .-■ 



presents several points of interest. The total number of species is a little over 200 ; and 

 very likely, when Madagascar is better explored, it will be raised to 

 with it as we know it at present, we find that more than half the species »M 

 in the tropical parts of the continent, that more than a quarter of ***> «£J"j 

 peculiar, L that it has a strong Indo-Malayan affinity, as the followmg anal} sis wdl 



show 



pecies known in Tropical Africa 



a 



it 



>} 



jj 



3> 



ti 



>> 



quite peculiar . 

 Tropical Asiatic 



Cape 

 American . 



Australian 



Tristan d' Acunha 



Temperate Asiatic 



Total 



90 

 56 

 40 

 12 



7 



3 

 3 

 2 



213 



The American species are, besides some 



already mentioned for West Africa, ITymeno 



me American species are, oesm^ — Asmi l km mo hrioldes, Polypodiurn pan 

 Phyllum lineare, Nephrodium contermutum, Aspiamm g ^ g 



