2l8 C. SKOTTSBERG 



Lactoris fernandeziana, Dendroseris macrophylla, macrantha, marginata and 

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

 pruinata, Hesperoseris gigantea. 



The ditierences 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 

 correspontling 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 affinity now referred to I a. Group 5, Pacific element, in- 

 cluded the new groups IV-VI 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%) and 2 to Masafuera, 

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

 single genus [Thyrsoptcris] is endemic in Juan P'ernandez and found on Masatierra 

 and Masafuera. 



Of the 53 s{)ecies 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 (^^.'jX, respectively. 



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

 or not isolated from the beginning, and Juan Fernandez 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- 

 cctUage 11.4, 22.9 and 65.7, respectively. The difi"erences 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 \ery 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. 



