154 



SCHIZAEACEAE 



[CH. 



Fig^ 437. Upper parts of fertile leaves of Schizaea. 

 C, D, S. elegans J. Sm. In D the ultimate segments 

 from Engler and Prantl.) 



A, S. pciiuida Sw. B, S. bifida Svv. 

 ire more highly magnified. (After Diels, 



1 881), but it is complicated by continued apical growth of the leaf as 

 a whole which is dichopodially developed, the lower sterile pinnae being 

 often broad, and the distal fertile pinnae narrower (Fig. 438). The whole 

 leaf may attain a length of 100 feet or more: it acts as a prehensile climber, 

 reaching very considerable heights in scrub and low forest (Vol. I, p. 35, 

 Fig- 43)- I" Anemia and Mohria the leaves are of more ordinary type: 

 they are less complex, and the reference to dichotomy is not so clear owing 

 to dichopodial development (Fig 439). The venation is usually open, but 

 some species of Lygodium and of Anemia show vein-fusions near to the 

 margin. In Mohria the sporangia may be distributed over the whole length 

 of the fertile leaf: in Schizaea and Lygodium the fertile region is distal: but 

 in Anemia as a rule only the two lowest pinnae are fertile, thus suggesting 

 Roeper's well-known theory of the origin of the fertile spike in Ophioglosstim 

 (Fig. 440). Dermal appendages are present in all the genera, and in all 



