THE VEGETATION OF THE JL'AN FERNANDEZ ISLANDS 879 



Scandent ferns. 



Arthropteris altescandens (Colla) J. Sm. ICndemic; both islands, but rare on 

 Masafuera; not uncomon in the lower forest belt on Masatierra from \'alle Fran- 

 ces to Ouebrada Juanango, but not observed at a greater altitude than 400 m. 

 Trailing over stones and fallen trunks and winding in the trees (PI. 95: i, see 

 also PI. 9, Skottsb. 2). 



BlccJinum Schottii (Colla) C. Chr. Endemic and not uncommon in the forests 

 of Masatierra, also in the upper montane region. Seems to be rare on Masafuera. 

 Fronds of much firmer texture than in the former, dark green and longer, to 

 50 cm, exceptionally large ones 90 cm long. Skottsb. ?, PI. 7: 3; pi. 80. 



Epiph\-tic ferns. 



Numerous ferns, most of them belonging to the HymeJiophyllaceae, which 

 will be treated separately, clothe the moss-covered trunks of the trees but arc just 

 as often found on the forest floor. Among the Polypodiaceae, AsploiiuDi dareoides 

 Desv. (magellanicum Kaulf.) and BlccJunoii I'aldiviense C. Chr. are epiphytic on trees 

 and tree-ferns, but also terrestrial. The small Polypodhan Billardieri (Willd.) C. 

 Chr., a very rare species in these islands, was seen growing in moss on Drimys 

 on Masatierra, and on a moss-covered rock on Masafuera; the common P. Ia7i- 

 ceolatuDi L., often met with in both islands though more plentiful on Masatierra, 

 is rarely terrestrial; on PI. 82 it is seen covering the branches of a fallen luma, 

 its slender, wiry rhizomes interlaced with the thick rhizomes of P. mtermediiDu. 

 The fronds are coriaceous in the former, which is a typical xerophyte; in cases 

 they are as much as 25 — 35 cm long, but generally much smaller. 



Polypodiuui intermediu)n Colla (P. translucens Kze). With regard to the 

 polymorphism of this endemic species, see pp. 37 — 41, fig. 6, and p. 765. On 

 Masatierra it general!}- grows on Drimys. on Masafuera (subsp. inasafuera7iuni 

 C. Chr. et Skottsb.' on Myrceiigenia. A couple of small plants were once found 

 on each of the islands, growing on moss-covered rocks near the sea (p. 38, fig. 

 6 d and p. 'j(^'>\ their fronds were stiff and coriaceous, whereas the epiphytes 

 have herbaceous fronds with the net of \"eins clearh^ visible when the frond is 

 held against the light. Plants of the typical species are seen on PI. 82. Thanks 

 to the succulent, water-storing rhizome (Fig. 29) they are able to withstand long 

 periods of drought. The colour of the rhizome is a light grayish green and the 

 numerous scales are reddish brown. The rhizome is flattened dorsiventrally, in 

 section e. g. 15X10 and 20X5 mm. Johow has published a ver\- good illustration 

 of this fern [2, PI. XVIII, P. translucens). 



In order to test the drought resistance a simple experiment was arranged 25.3. 17. 

 The apical portion of t^^•e plants (1 — V) of the typical form were detached from the 

 substratum, carefully cleansed from mosses and lichens and the cut end sealed with 

 grease. They were hung on the veranda protected from the rain, but exposed to tull 

 light. They were weighed every 48 hours until 1S.4, when the inters'als were prolonged, 

 and the experiment was finished 29.4 because we had to prepare to leave the island. 

 The results are accounted for in Table XXV. 



