VASCULAR PLANTS. 155 



7. Adiantum, L. 



Sporangia at the ends of distinct veins. Sori 

 covered by the semi-lunar reflexed margins. In- 

 dusium continuous with the margin, free on its 

 inner side 



21 . petioles not green. 



8. Blechnum, L- (Lomaria, Willd.) 



Sporangia forming a linear sorus on each side 

 of the midrib and parallel to it. Indusium 

 membranaceous, attached to the receptacle and 

 free on the inner side. U . 



9. Woodwardia, L. 



Sporangia placed on reticulate veinlets, form- 

 ing oblong sori on each side of the midrib. In- 

 dusium coriaceous, attached to the receptacle, 

 and opening at the inner side. 2f . 



10. Asplenium, L. 



Sori linear, placed on veinlets. Indusium 

 membranaceous, attached laterally to the vein- 

 let and opening towards the midrib. U • 



11- Aspidium, Swartz. 



Sori round, placed at the end of the veinlets. 

 Indusium umbilicate, free on all sides and af- 

 fixed by a column. 11 . 



12. Cystopteris, Bernharci. 



Sori round, placed on the middle of the vein- 



