M. ATHYRIUM. 427 



x.x. Indusium not reniform. ' (Sc) A. Copelandi. 



:i\!:.^. Fully developed fronds larger, more than iO c.M. broad. 



(4) A macrocarpum. 

 ■^.•^. Lower pinnae reduced. (5) A. acrostichoides. 



6.6. At least the lower pinnae pinnate to 2-pinnate. (') 

 c. Fronds small, under i5 c.M. long. (^) 



$. Rhizome creeping, often intertwined. (6) A. hyalostegium. 

 $.$. Rhizome short, erect. 



>K. Fronds ± as broad as long. (7,) A. Loheri. 



i(^.if. Fronds + 2 X, as long as broad. (8) A. Sarasinorum. 

 c.c. Fronds larger, more than i5 c.M. long when Jullij developed. 

 d. Teeth of the segments finely aristate, retroflexed. 



(9) A. arislulatum. 

 d.d. Teeth whether or not aristate, not retroflexed. 



e. Lower or costal sori often horsesh oe-shaped or hamato-reniform . 

 X. Texture herbaceous. (10) A. solenopteris. 



x.x. Texture coriaceous. (11) A. drepanopterum. 



e.e. Largest sori hamato-recurvate at the apex only. 



(12) A. nitidulum. 

 e.e.e. Sori straight or slightly curved, the lower sometimes 

 double. , 



f. Costae or costulae beset with distant, subulate, 

 firm or flaccid appendages on the upper side. 

 * Fronds to 12 cm. broad,- with the central 

 pinnae the largest. 



(13) A. gymnogrammoides. 

 *>)<: Fronds more than 12 cm. broad, or the 

 central pinnae not the largest. 



(14) A. nigripes. 

 f'.f. Costae and costulae without subulate appendages. 



g. Tcrliary^segm^ts elliptico-rhomboidal, the base 



narrowed or + ^eSTJjjBejj^ (IB) A. umbrosum. 



g.g. Tertiary segments linear-obBSff;-<llie base not 



narr(mwd, not decurreni, (16) A. an^^ J ttewi H. 



(') See also A. macrocarpam, Bedd. 

 (') See also A. arlstulatum, Copel. 



