2l8 C. SKOTTSBERG 



Lactoris fernandeziana, Dendroseris macroph}-lla, niacrantha, marginata and 

 litoralis, Phoenicoseris pinnata, berteriana and regia, Rea neriifolia, micrantha and 

 pruinata, Hesperoseris gigantea. 



The dift'erences between this arrangement and the one of 1934 are consider- 

 able, but partly at least more apparent than real. Group i of 1934 corresponds 

 (if we exclude (b), which from a purely geographical point of view has to go to 

 the present group II) to I, but Selkirkia has now been placed in III, a group 

 corresponding to the 3d element of 1934. Group 4 was rather heterogeneous and 

 included, beside Magellanian species, several bicentric ones and some endemics 

 of austral-circumpolar affinit}' now referred to I a. (}roup ;, Pacific element, in- 

 cluded the new groups IV-\T and part of III. 



II. Pteridophyta. 



Six families (taken in the old sense) are represented, Ophioglossaceae only 

 on Masatierra, Lycopodiaceae only on Masafuera. The number of genera is 23; 

 21 (91.3%) are found on Masatierra and the same number on Masafuera, 3 on 

 Santa Clara. Two genera are confined to Masatierra (8.7 %j and 2 to Masafuera, 

 19 (82.6%) shared by both islands, 3 of them also known from Santa Clara. A 

 single genus {Thyrsopteris) is endemic in Juan F"ernandez and found on Masatierra 

 and Masafuera. 



Of the 53 species listed 43 occur on Masatierra, 3 on Santa Clara and 45 

 on Masafuera. Only 8 species are restricted to Masatierra, 15.1% (18.6% of the 

 total found there) and 10 to Masafuera, 18.9% (22.2% of the total); 35 (66%) 

 are found on both. 



There are 18 endemic species (34%), of which 16 inhabit Masatierra and 14 

 Masafuera; no endemic is found on Santa Clara. Of the endemics 4 are confined 

 to Masatierra and 2 to Masafuera, 12 having been recorded from the two islands; 

 in percentage: 22.2, ii.i and 66.']%, respectively. 



A high percentage of ferns is to be expected in "oceanic" islands, whether 

 or not isolated from the beginning, and Juan P^ernandez is no exception from this 

 rule, for of the 200 vascular plants 26.5 % are Pteridophytes. 



Of the 35 species also found elsewhere 4 are confined to Masatierra, 8 to 

 Masafuera and 23 found on both islands, 3 of these also on Santa Clara; in per- 

 centage 1 1.4, 22.9 and 65.7, respectively. The differences in percentage between 

 endemic and non-endemic species is due to the occurrence, in the highland of 

 Masafuera, of a few mountain ferns not found on the other island. But whether 

 our analysis bears upon families, genera or species the distribution over the archi- 

 pelago is very much more even than the dispersion of the angiosperms, and this 

 is of course what we have every reason to expect. Also, the number of species 

 to a genus is greater, 2.3. 



