ON THE CLASSIFICATION OF FKBNS. 95 



( Fronds tufted, of two sorts, the central ones erect, fruiting, 



5 < the outer ones barren, usually shorter, with broader lobes 6 



( Fruiting and barren fronds similar, or nearly so 8 



Fronds (stiff) simply pinnate, with entire lobes, the fruiting 

 linear, the barren lanceolate , BLECHNUM. 



Fronds (delicate) much divided, with small, obovate or 

 oblong toothed lobes 7 



Sori forming a line close to the margin of the frond. 

 - ALLOSORUS. 



Sori oblong, scattered on the surface of the frond. 



GYMUOGRAMMA. 



f Fructification concealed by, or intermixed with, chaffy 



scales or hairs 9 



o J Fructification in lines along the margin of the fronds, the 



I indusium a membrane attached to the margin 10 



Fructification in circular, oblong, or linear sori, on the under 

 t surface, without chaffy scales 11 



Fronds deeply pinnatifid, with entire segments. Sori linear, 

 concealed by the scales 10. CETERACH. 



Fronds twice-pinnate, with small segments. Sori circular, 

 with chaffy hairs intermixed 15. WOODSIA. 



( Tall, erect, stiff fern, ternately divided, with pinnate 



. ,. \ branches and sessile lobes PTERIS. 



i Delicate fern, not a foot high, much divided, with broad, 

 ( wedge-shaped lobes on capillary stalks .... ADIANTUM. 



(Sori oblong or linear, covered (when young) with a mem- 

 brane attached along the side 12 

 Sori circular, either without any indusium. or covered (when 

 young) with a membrane attached by the centre or by a 

 lateral point 13 



Frond entire. Indusium opening in a slit along the centre. 



,n SCOLOPENDRIIJM. 



Frond pinnate or much divided. Indusium opening along 

 the inner side ASPLENIUM. 



Fronds simply pinnate, with entire or toothed segments or 

 pinnaa 14 



Fronds pinnate, with pinnatifid primary divisions or pinnas, 

 or twice or thrice pinnate* 15 



I 



13 



* In all twice or thrice pinnate leaves or fronds, the primary 

 divisions on each side of the main stalk are called pinnas, the 

 ultimate divisions retaining the name of segments. 



