chap, in The Study of the Cryptogams 239 



by De Bary in 1858, and the first prothallus identified was 

 that of L. annotinum. This was investigated by Fank- 

 hauser in 1873, and held by him to indicate an affinity with 

 Ophioglossum. Bruchmann confirmed Fankhauser's work in 

 1885. Much of our knowledge of this subject is due to 

 the later researches of Treub, which extended from 1884 

 to 1890 ; in the course of them he examined very thoroughly 

 the structure of the prothallium, and the development of 

 the embryo of several species, and in fact laid the founda- 

 tion of the knowledge of the group. He found that in 

 some cases a mycorrhiza is present. Later in the century, 

 in 1898, Bruchmann added the elucidation of prothallia of 

 four more species, one of which, L. clavatum, was also found 

 by Lang in the same year and described very completely 

 in 1899. 



Phylloglossum was first investigated by Mettenius in 

 1867, but our knowledge of its structure is mainly due to 

 the researches of Bower, who worked out its anatomy in 

 1885 ; he also followed out the germination of the tuber 

 and the formation of the vegetative parts from it. Bertrand 

 in the same year investigated the mature strobilus and the 

 vegetative organs. 



Juranyi first carried out researches on Psilotum, dealing 

 with the internal structure of the sporangiophore in 1871 ; 

 Strasburger made a more complete examination of the 

 anatomy in 1873, and was followed by Bertrand in 1885. 

 In 1884 Solms-Laubach investigated the development of 

 the sporophyte, and especially of its sporangiophore. 

 Tmesipteris was the subject of researches by Goebel in 

 1881, and by Dangeard in 1891. 



Millardet's work of 1869 on the male gametes of the 

 Pteridophytes included those of Selaginella, but a more 

 important research was made by Pfeffer in 1871, which 

 was largely concerned with the processes of germination 

 of its spores, the development of its prothallia, and the 



