I/O 



SCHIZAEACEAE 



[CH. 



the periclinal division which separates off the cap-cell from the archesporium. 

 The former gives rise to the greater part of the sporangial wall, while the 

 lower segments complete the wall, and form the short thick stalk. From the 

 archesporium the usual tapetum and sporogenous group arise: the tapetum 

 may sometimes be irregularly 3-layered, while the spore-mother-cells are 

 more numerous than in ordinary Leptosporangiate Ferns. In Anemia and 

 Mohria 16 of them may be seen in a single section, and in Lygodmni as 

 many as 20 (Fig. 456).' An enumeration of the spores actually produced 



Fig. 455. Diagram showing the segmenta- Fig. 456. Section through a sporan- 



tioninayoungsporangiumoftheSchizaea- g\\m\o{ Lygodiiimcircinatum. (After 



ceae. The first segment-wall meets the Binford.) 20 spore-mother-cells are 



basal (periclinal) wall of the parent-cell: cut through; the tapetum is more 



but the second ( x , x ) meets the first, and than doubled. ( x 480. ) 

 does not extend to the base of the parent- 

 cell. 



shows that in L.javanicum and dichotomuin the numbers indicate a typical 

 number of 256, while in L. pinnatifidum there are only 128. There is thus 

 a difference between species of the same genus, as has already been seen in 

 Todea: the lower figure is shared by Schizaea, Mohria, and Anemia. Thus 

 the numbers approach those found in the Osmundaceae: and the largest 

 number appears in Lygodium, a genus where the anatomy is more archaic 

 than in the rest of the Family. 



The Gametophyte 

 The spores of the Schizaeaceae vary in type. In Lygodium, Anemia, 

 and Mohria they are tetrahedral, but in Schizaea they are wedge-shaped. 

 Their walls are marked by more or less projecting ridges, but they are 

 without any deposit of perispore. On germination the same three genera 

 form flattened prothalli of the usual type, but with lop-sided growth, and 

 a lateral cushion (Bauke, Pringsh. Jahrb. Bd. xi, 1878). This is not so, 

 however, with Schizaea (Britton and Taylor, To7^r. Bot. Club, xxviii, 1901 : 

 Thomas, Ann of Bot. xvi, p. 165: Goebel, Organographie, Aufl. ii, p. 957: 

 Campbell, Mosses and Ferns, 3rd Edn., p. 384). In S. pusilla, rupestris, and 

 bifida it has been seen that the prothallus is filamentous, bearing on short 



