214 ^- SKOTTSBERG 



These were (the species from Masatierra mentioned first): Dendroseris Diicrantha- 

 gigantea (belong to dififerent genera), Wahlenbergia Berteroi-tuberosa [= Masa- 

 fuerae, not very closely related), Myrceiigenia fernandeziana-Schulzei {^\^^x^x\\. 

 genera), Eryngiiim bupleuroides-sarcophyllum (only distantly related), Cardatniue 

 alsophila [ = Jlaccida)-Kri{essc Hi [not nearly related), and Urtica gloinemliflora ( = fer- 

 nandeziana)- Masafuevae (belong to dififerent sections). There is not among them 

 a single example of either vicarism or pseudo-vicarism in the sense of ViEKiiAPPER. 

 In 1914 [22^] I distinguished 4 pairs of vicarists in Juan I^'ernandez: Dendro- 

 seris micrantha- gigantea, Myrceugenia fernandeziana- Schulzei, Gumiera peltata- 

 Masafiierae, and Peperoniia margaritifera-Skottsbergii\ the flora of Masafuera was 

 at that time little known. Of these pairs the last two still hold good, the species 

 replace each other from a taxonomical as well as from a sociological viewpoint; 

 nevertheless I am not prepared to argue that they arose out of one initial spe- 

 cies: several species may have been involved, for they differ in a number of 

 minor characters and all we can say is that they make the impression of coming 

 from the same stock. On the basis of our present knowledge of their taxonomy 

 the following nine pairs are distinguished; the species replace each other, call 

 them vicarious or substitute: Berberis corymbosa-masafuerana, Chenopoditini crii- 

 soeaman-nesodendron, Dendroseris macrantJia-macropIiylla, F agar a niayu— externa. 

 Gunner a peltata — Alasafuerae, Halorrhagis masatierrana-niasafuerana, Pepero7nia 

 niajgaritifera—Skottsbergii, Robinsonia eveyiia — JMasafnerae, and Sophora fernan- 

 deziajun— niasafuerana. As regards Berberis, Fagara, HalorrJiagis and Sop/iora, 

 perhaps also Gnnnera, Peperoniia and Robijisonia, the two members of a pair are 

 closely related, but in the case of Halorrhagis the situation is complicated be- 

 cause there is a third species, endemic in Masafuera, H. asperrima; niasafuera?ia 

 seems, however, to be a better match for niasatierrana than asperrima. As we 

 have seen, there is also a third species of CJienopodiuni, endemic to Santa Clara, 

 very likely formerly occurring also on Masatierra, but extinct there. Of the 3 

 species of Dendroseris inhabiting Masatierra, niarginata and litoralis form a pair 

 of one inland and one coast species. 



An unbalanced flora. 



It has always been argued that an island flora, where the number of species 

 is small compared with the number of genera and many large and widely distri- 

 buted families, well developed under different conditions, poorly represented or 

 altogether absent, furnishes one of the best proofs of the absolute oceanity of its 

 abode, and Juan Fernandez is no exception from this rule. I have mentioned this 

 above (p. 194) pointing out that most of these families have numerous genera 

 and species on the opposite mainland, thus Caryophyllaceae 20 genera, Compo- 

 sitae some 130, Cruciferae 28, Leguminosae 22, Scrophulariaceae 18, Umbelliferae 

 about 30, and so forth, and examples of important families in Chile not found 

 in the islands were also given. This state of things calls for an explanation. JOHOW 

 paid much attention to it; as he believed that the islands had been isolated from 

 the very beginning he blamed chance in all cases where, according to the cur- 

 rent opinion, the diaspores were adapted for dispersal across a wide expanse of 



