130 VI. POLTPODIACEAE. § ». BLECHNEAE. 



*. Veins of sterile fronds free, those of the fertile ones unitet 

 near the base by subcostal strands bearing the sori. 



No. 49. BIcchnum 



4,.A. Veins of both sterile and fertile fronds united near th( 



base. No. 50. Sadleria 



2.2. Sori oblong, in 1 or more rows on each side of the midribs, 



not + close to the latter. No. SI. Uoodia 



J.f. Sori immersed in cavities, oblong, in 1 row on each side of th( 



midribs of the ultimate segments. No. 52. IV^ooflwarclia 



§ 6. ASPLENIEAE. 



a. Sori between the veins; indusia 2 to each sorus, springing from the 

 inner side of the 2 contiguous veins, opening towards one another. 



No. 57. Triphlebia 

 a.a. Sori springing from the sides of the veins like the indusia; indusia 

 1 to each sorus. 



b. Stipes with 2 + flattened vascular strands mostly uniting towards 

 the apex (of the stipe) or higher into a single diarchous one 

 ( \ / , \/, \ / , |_J, [_)). Scales of the rhizome finely cancellate, 

 the areolae mostly dark-coloured. 



c. Sori and indusia mostly long and straight; the lower sori 



and indusia of the same group of veins often, the higher 



ones rarely double, i. e. 2 opposite sori and indusia to a 



single vein. No. 55. Oiplazium, 



C.C. Sori and indusia mostly short, often curved, sometimes hamate 



or horseshoe-shaped, the higher ones never, the lower rarely 



double. No. 54. Athyriuiu. 



6.6. Stipes vnth 2 + concave vascular strands mostly uniting towards 



the apex (of the stipe) or higher into a single tetrarchous out 



[ ) G X' )—{> >—' \ . X. V> \ / 1- Scales of the rhizome coarsely 



cancellate, the areolae mostly decoloured. 



*. Sori in opposite pairs; indusia opening towards one another. 



No. 56. Phyllitis 



;(c.*. Sori not in pairs; indusia opening tovpards the costa oi 



occasionally towards the margin. No. 55. Aspleniiim 



