38o MOSSES AND FERNS chap. 



The Ganietophjte 



The first account of the development of the sexual stage 

 of the Salviniaceae that is in the least degree accurate is 

 Hofmeister's/ who made out some of the most important points 

 in the development of the female prothallium. Pringsheim's ^ 

 classic memoir on Salvinia added still more, as well as Prantl ^ 

 and Arcangeli,"^ but none of these observers were able to follow 

 accurately the earliest divisions in the germinating macrospores. 

 Berggren's "^ account is the only one on the female prothallium 

 of Azoila, except a paper by the writer, but Belajeff ^ has given 

 an excellent account of the germination of the microspores. 



The Male Prothalliwn 



The microspores at maturity are embedded firmly in a mass 

 of hardened protoplasm, which in Salvinia fills the whole 

 sporangium, in Azoila is divided into separate masses, " mas- 

 sulse." The wall of the sporangium in Azoila decays and sets 

 these free in the water, but in Salvinia the wall of the 

 sporangium is still evident when the germination takes place. In 

 the latter the young prothallium grows into a short tube, whose 

 basal part is separated as a large vegetative cell, from whose 

 base later, Belajeff ' states, a small cell is cut off. The upper 

 cell becomes the antheridium. In it is first formed in most 

 cases an oblique wall, which Belajeff states is always followed 

 by another similar one, which forms a central sterile cell 

 separating the two groups of sperm cells. This cell, however, 

 did not occur in the specimens studied by me, when the tv/o 

 groups of sperm cells were usually in immediate contact (Fig. 

 1 96, E). From each of the upper cells peripheral cells are cut 

 off, but they do not completely enclose the sperm cells, which 

 are in contact with the outer wall of the antheridium. A cover 

 cell corresponding to that in the ordinary Fern antheridium is 

 more or less conspicuous. Each of the central cells divides 

 by cross-walls into four, and there are thus eight sperm cells in 

 the ripe antheridium. The spermatozoids of Salvinia have 

 about two complete coils, and a smaller number of cilia than is 

 usually the case in the Filicineai (Fig. 1 96, G). 



^ Hofmeister (i), p. 328. - Pringsheim (i). •'^ Prantl (4). * Arcangeli (i). 



■^ Berggren (2). " Belajeff (3). '' Belajeff (3) in Bot. Centralblatt, 1892, p. 328. 



