80 



G 1 e i c li e n i a. 

 The Prothallium and Embryo. 



With the exception of the monotypic Stromatopteris, all of 

 the species of Gleicheinaceae are usnally referred to the genus 

 Gkichenia, which is, however, often divided into several snb- 

 genera. The species are mostly tropical, some like G. dichotoma 

 {G. linearis [BuiiM.] Bedd.) being very widely distril)nted, ac- 

 cording to Hooker and Baker occurring in the tropics of both 

 the old and the new worlds and extending as far north as 

 Japan. It may be said, however, that Underwood in a recent 

 account of the American Gleicheniaceae asserts that the Ame- 

 rican species referred to G. dichotoma is very distinct and should 

 be referred to G. flsTcuosa Sen r ad. (Underwood, A preliminary 

 review of the North American Gleicheniaceae, Bulletin of Torrey 

 Botanical Club, 34, May, 1907). In the southern hemisphere a 

 number of species are extra-tropical, several occnring, for example, 

 in New Zealand and G. polypodioides is found in Africa as far 

 south as Capetown. In the northern hemisphere some species, 

 e. g. G. dichotoma, are fonnd in Japan, which forms the northern 

 limit of the genus. There are no species occuring in North 

 America outside of the tropics, and none are fonnd in Enrope. 



The material upon which the following account is based was 

 collected by the writer at different times, and includes species 

 from Jamaica, South Africa, Ceylon and Java. 



The only account of the development of the prothallium and 

 reproductive organs that has yet been published is that of 

 Kadvvenhoff (De geslachtsgeneratie der Gleicheniaceen, Natuurk. 

 Vei-h. der Koninkl. Akademie, Deel XXVIII, 1890), who studied 

 in detail the germination of the spores of several species, and 

 followed the development np to the time of the formation of 

 the reproductive organs. He also obtained a few embryos, but 

 his account of the embryo is very far from complete. The 

 writer has already figured the prothallium and reproductive 

 organs of G.pectinata (Mosses and Ferns, 2»'l Edit., Figs. 208-209), 



