THE THAI. LOSE HHPAIICAIC OK THE JUAN FKRNANOEZ ISLANDS 579 



SVV. slope, amoni( Dicksonia, 550 in. (no. 80); CJ. Gutierrez, 500 in. slope, among 

 Dicksoiiia, 550 in. (no, 80); Q. Guiterrez, 500 m. (no. 81). 



*Masat'iiera: O. del HliiuL-uio, moist rocks in forest, 440 ni. (no. 82). 



.\iva of" distribution: Juan {''crnandez; Falkland Islands. 



21. S. llynicnophylliiin (Hook.) iVIont. & Nees in G. L. & N. Syn. Hep. 

 480 (1846). — Syn. yiDigvrnumnia llyinoiophylluin Hook. Muse. Exot. pi. 14 

 (1818); Symphyogyna cJiilo'cnsis Steph. Kungl. Svenska Vet.-Akad. Handl. 46''; 

 12 (191 1); .V. lanceolata Steph. op. cit. 13 (191 1). 



On earth, especially in shade. 



Masatierra: on bare earth, base of El Vunque, Skott.SBERG, 1908 (no. 

 45, type of S. lanceolata Steph.); ridge between Q. Piedra agujeriada and Q. 

 Laura, 650 ni. (no. 83); Portezuelo, ravine on SVV. slope, among Dicksoiia, 

 550 m. (no. 83 a); C. Salsipuedes, Dicksonla forest, 660 m. (no. 84). 



*Masafuera: vicinity of the Campo Correspondencia, 1 100— 1150 m. (no. 

 85, 86, 87, 88, 89). 



In the dendroid species of Symphyogyna, which are typified by S. Hymeito- 

 phylluDi, the differentiation of the thallus is usually much more clearly marked 

 than in the decumbent species, to which 5. clrcinata and S. tlochstetteri belong. 

 The prostrate portion of the thallus consists of a wingless, terete rhizome, 

 densely covered with rhizoids. This curves upward and forms an erect and 

 more or less elongate stipe, destitute of rhizoids, which broadens out into the 

 characteristic, broadly winged, aerial portion of the thallus. The latter is 

 sometimes simple but usually branches by dichotomy from one to five times. 

 In typical cases the dichotomies are close together, the brandies of each rank 

 are subequal in length, and the thallus forms (in the more complex examples) 

 a flat branch system, spreading more or less horizontally and showing a sub- 

 circular outline. The ultimate branches of the system are limited in growth 

 and not infrequently develop apical wings. Between the complex branch-system 

 just described and the unbranched winged thallus, which usually departs but 

 slightly from a vertical position, all possible gradations may be demonstrated. 

 The conditions may be further complicated by the phenomenon of reversion, which 

 sometimes takes place when an aerial thallus or one of its young branches comes 

 in contact with the substratum. Under these circumstances the wings narrow 

 and disappear, and the thallus continues its growth as a terete rhizome with 

 rhizoids. Aside from the dichotomous branching exhibited by the aerial thalli, 

 the rhizomes and the bases of the stipe usually give rise very sparingly to 

 intercalary branches. These grow out horizontally in the form of new rhizomes, 

 which in turn develop new aerial thalli. It this way extensive colonies of such 

 thalli may be formed, more or less intimatel)^ connected subterraneously. The 

 conditions just described are strikingly paralleled by HymenopJiytuui flabellatiwi, 

 as already pointed out by GOEBEL and other writers. 



The dendroid species of Synip/iyogyna are in need of careful study, not 

 only in the herbarium but also in the field and under cultural conditions. When 

 the descriptions given in the literature are compared it will be seen that some 



