1 66 



SCHIZAEACEAE 



[CH 



Fig. 450. Longitudinal section through the apex of a pinna of 

 Moh?'ia caffronun, showing the apparently superficial position 

 of the sporangium, which is actually marginal in origin. This 

 appearance is due to the active growth of the indusium from 

 its base, forming a false margin. ( x 75.) 



elegans, with a rosette-type of shoot, and leaves not speciaHsed for protection 

 against drought, Hke the rest (Fig. 446). The adult fertile leaf shows 

 a sympodial dichotomous venation of the same plan as is seen in the 

 juvenile leaves of Anemia (Fig, jy, Vol. l), or of Osnmnda (Fig, 416), and it 

 closely resembles also that of Botrychiuni and Helniinthostachys (Vol. I, 

 Fig. 81), This plainly proves that the architecture of the leaf is based on equal 

 dichotomy, and not very far advanced from that state sympodially. Fig. 446 

 also shows the sporangia grouped, as in Anemia, at the ends of the veins of 

 the two broad basal pinnae. Assuming that their origin is marginal like 

 the rest of the family and of the genus, while they are sometimes solitary 

 as they constantly are in Mohria, this simple leaf is itself a near approach to 

 that primitive leaf contemplated in an archetypic Fern (Vol. I, Chapter XVII, 

 p. 339). A lateral webbing of a dichotomous leaf, each branch or vein of 

 which bore a distal sporangium, would give such a leaf as MoJivia, excepting 

 for the secondary displacement and protection of the solitary sporangia: or 

 it would give that of Anemia ckgans if the number of the distal sporangia 

 were increased by interpolation along the margin. This is the hypothetical 

 reading of such sporophylls of the Schizaeaceae which naturally follows 

 from the study of their development, together with a comparison of other 

 primitive types of Ferns (Goebel, Anemia elegans, Flora, Bd. 108, p. 319). 



