DERIVATION OF THE FLORA AND FAUNA 28l 



beyond doubt, and A. altescajidens has its nearest allies in Oceania; comp. above 



p. 222. 



Aspleniwn. CoPELAND points out that some groups at least are southern and 

 that perhaps the same applies to the whole genus: "it migrated in its present 

 form from Antarctica" {6g. 167). Of the species found in Juan Fernandez, obliquum 

 is austral-bicentric, stellaimn close to neotropical species, macrosorum most likely 

 of neotropical affinity; day^eoides comes very near alvarezerise from Tristan da 

 Cunha and is not, as has been suggested, related to the boreal ruta muraria. 



Blechnum. According to Copeland (^9.157) no fern genus is more con- 

 spicuously austral in its present distribution and thus more evidently Antarctic 

 in origin. Of the 6 species found in Juan Fernandez auriculatmn , chilense and cy- 

 cadifolium belong to an Afro-american group, Schottii and perhaps also valdiviefise 

 of austral-circumpolar type, and longicauda intimately related to the neotropical 

 Spriicei\ even so it cannot blur the picture of an old Antarctic genus. 



Pellaea is an austral-tricentric genus extending north to Canada, but P. chi- 

 lensis, endemic in Juan Fernandez, but dangerously close to a widespread American 

 species, belongs to a group that, according to Copeland [6^. 70), is best allowed 

 to form a separate genus; I have brought it to the neotropical element. 



Hypolepis is pantropical, especially neotropical, but numerous species are 

 scattered in the equatorial and austral zones: Africa with neighbouring islands, 

 Malaysia and north to Japan, Australia-New Zealand-Lord Howe-Melanesia-Hawaii 

 — when Copeland said "without surviving Chilean representatives" he 'iox^otrugo- 

 sula. This species is bicentric or, including Polypodium villosoviscidum of Tristan, 

 tricentric; there is another variety on St. Helena. Thus when CoPELAND 6y. lyy 

 calls Hypolepis "an old antarctic genus now at home chiefly in the Tropics but 

 with two of its paths still occupied", we can add that also the third path is indicated. 



Adimituin is most numerous in S. America, and A. chilense and related species 

 tell us nothing of the earlier history of the genus; CoPELAND 6g. 78: "I suppose 

 that at least the most of the extant species are of Antarctic ancestry, but the 

 genus is old and may have lived elsewhere without interruption"; in dy. 178 he 

 says that "Antarctica has played a major part in its history", but that the genus 

 "may include elements surviving from other floras and from an age prior to the 

 great dispersal from the south". I refer A. ckilefise to the neotropical group. 



Pteris. The great wealth of species is in the tropics and only few extend as 

 far south as to south Chile, S. Africa and New Zealand. P. chileiisis is of neo- 

 tropical character, perhaps also P. semiadnata, while berteroana belongs to a group 

 regarded by CoPELAND as Antarctic to judge from its distribution pattern (see 

 above p. 223). 



Histiopteris incisa is a pantropical and circum-austral, polymorphous fern with 

 a number of "local derived species" (Copeland) in Indonesia and Polynesia. The 

 genus is, Copeland says [6g.6o), "evidently old enough to be a migrant from 

 Antarctica". 



Polypodium is an aggregation of unities of different origin and history. Gram- 

 mitis is, in Copeland's opinion (<57. 184), "a plain Antarctic case", and G. Bil- 

 lardieri "surrounds Antarctica more closely and completely than does any other 



