CLASSIFICATION OF FEKNS. 
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/. var. Howardii. Upper pinnae curiously dis- 
torted. 
g. var. cristatum. Fronds crested. 
h. var. glandulosum. Glands much developed. 
i. var. crispum. Leaflets crisped and waved. 
j. var. tenerum . Fronds weak and delicate! 
7. N. dilatatum s Fronds ovate, tripinnate ; leaflets 
sharply serrated. 
8. N. (Emulum . Fronds triangular, bipinnate ; pinnules 
concave below. 
a . var. alatum . Fronds quadripinnate. 
b. var. productum . Fronds shorter, less divided. 
9. N. dumetorum. Fronds ovate, blunt; leaflets broad. 
10. N. remotum. Fronds oblong, lanceolate, glossy bi- 
pinnate ; lower pinnae distant, stalked. 
6. Cystopteris. 
1. C.fragilis. Fronds lanceolate, bipinnate; pinnules 
ovate, acute ; sori central. 
a . var. dentata . Pinnules ovate, acute, distant. 
b. var. Dickieana. Pinnules broad, obtuse, over- 
lapping. 
c. var. angustata . Fronds pointed ; pinnules 
sharply cut. 
2. C. alpina. Fronds tripinnate ; segments linear. 
3. C. montana . Fronds triangular. 
7. Asplenium. 
1. A. septentrionale. Fronds linear-lanceolate 2- or 3- 
cleft. 
2. A . Germanicum. Fronds linear, pinnate ; pinnae 
alternate, narrow wedge-shaped ; involucre 
entire. 
