544 



FILICALES 



by curling over of the margin of the pinnule, as in ^f<>Ilria and Schizaea, 

 and in some degree in Anciniia : or there may be a special protective 

 growth, comparable to the indusium of the Hymenophyllaceae, which 

 completely covers each separate sporangium, as in Lygodium (Fig. 301). 



FIG. 301. 



Disposition of the sporangia of the Schizaeaceae. A = Sc!t. dichotoma, J. Sm., part of 

 a fertile segment (sorophore). B, C.= Lygodium japonicum, Sw. />' = apex of a young 

 fertile segment. C= mature fertile segment, at (_r) the sheaths have been removed, so as 

 to display the sporangia. /' = Mohria caffroruni (L.) Desv., segment of a fertile pinna. 

 fc, F=Aneina Phyllitidis, S\v. /'~ = side view of a young fertile segment. /'=fertile 

 segment from below (A, B, after Prantl. C, />, Rafter Diels, from Engler and 

 I'rantl, ,\'af. Pflanzenfam.'). 



SPORE-PRODUCING M KM I-.KKS. 



These in the Schizaeaceae are simply the solitary sporangia, each of 

 which Prantl recognised as constituting a " monangial sorus." He accurately 

 worked out their development, and found them to arise in acropetal order 

 on each fertile segment : he ascribes to them all an origin from cells of 

 the marginal series, with a terminal position on the fertile vein. Con- 

 sequently the protecting flanges must, according to his account, be accessory 

 growths from the aclaxial surface of the leaf. As Diels remarks, however, 

 extended and renewed investigations are desirable before this is finally 

 accepted. 1 It seems improbable for Schizm-a, and still more so for certain of 

 the related fossils : from their mature position in these it would appear 



1 j\'iit. /'/lan:t>i/iii., i., iv. , p. j6o. 



