I 8 CARL CHRISTIANSEN AND CARL SKOTTSBERG 



According to observations on living specimens and from a comparison 

 of the material at hand we conclude that the Dicksonia which inhabits Masa- 

 fuera differs from the type and deserves a special name. It is found growing 

 in the higher forests, where it may form dense % stands along the streams, and 

 many groves are seen above the upper limit of the forest and on the grassy 

 slopes of the ridges, though rarely below 500 m. On the slopes of Los Ino- 

 centes there is a contiguous belt of Dicksonia, forming an extensive, low, but 

 exceedingly dense forest which offers considerable difficulties to the explorer; 

 it may, however, be crossed along the Vacas ridge where it has been accident- 

 ally burnt in places. It reaches the altitude of about 1200 m. North of the 

 Casas canyon, in the heath, scattered specimens are found; the last were met 

 with at 1 1 70 m. It is scarce in the northern and less humid parts of the is- 

 land and was not seen by us at the tributaries to Q Sanchez. We gathered 

 fruiting specimens in August, 1908, but no ripe ones were found before our 

 departure in 1917, March 15. 



Masafuera: Q. del Mono, in the woods from 475 m; in the Antkoxan- 

 thum meadow on the higher slopes, from 530 to 1170 m; C. del Barril, not 

 uncommon above 750 m; Q. del Blindado, forest ravine, 440 m (no. 515); Los 

 Inocentes, scattered clumps below 750 m, thence forming closed groves, which 

 dissolve at an altitude of 11 — 1200 m. 



Area of distribution: Endemic. 



Polypodiaceae. 



Cystopteris Bernh. 



19. C. fragilis (L.) Bernh.: C. Chr. Ind. 203. — C. fragilis var. canari- 

 ensis (Willd.) Milde Fil. Eur. 152 sec. C. Chr. Arkiv for Bot. 10: 5 (1910). 



Wet, shaded and sheltered corners in the deep canyons. (Fertile Aug., 

 Feb.) 



Masafuera: Q. de las Casas, under overhanging rocks (no. 508); Q. Lo- 

 belia, exterior part of the gorge, under large stones. 



Detected by SKOTTSBERG in the Casas valley, 1908. The present speci- 

 mens are identical with those from 1908 which were referred to var. canari- 

 ensis, and they certainly fall under this variety as circumscribed by MlLDE. 

 Still the variety comprises many rather different forms, and the form from 

 Masafuera cannot very well be associated with the one from the Atlantic is- 

 lands under the same name. It is a large, very thin-leaved form with fronds 

 up to 30 cm long and with large sori; the lower side is rather glandulose- 

 pubescent. Probably it is almost the same as var. fumarioidcs (Pr.) [Athyrium 

 fumarioides Presl, Rel. Haenck. 1: 39 tab. 6 f. 2), based on Peruvian plants. 



Since MlLDE revised the numerous forms no pteridologist has tried 

 to unravel the taxonomy of the species with due regard to geographical 

 distribution. 



