17 
the mid-rib. The plants of this genus have generally a stiff 
form and a polished stalk. 
3. Scaly Spleenworts. Ceteraclu Clusters linear, straight. 
Covers narrow, upright on each branch of side-veins. Side- 
veins unite and form a net- work. Back of leaflets enveloped 
in chafiy scales. 
4. Hartstongue. Scolopendrium, Clusters and covers in 
pairs, one seated on the upper and the other on the lower 
branch of each side-vein, and opening to face each other. 
Plate II, fig. 17. 
Family IV. 
IV. Maidenwoets. AdiantecB, Cover linear, either paral- 
lel to the edge of the leaflets, or formed by their bent-back 
edges. 
2 Genera, 
1. Hard Ferns. JBlechna, Bags of spores lying in a long 
straight line. Side-veins of fruit-bearing fronds joined by 
a line somewhat parallel to the mid-rib. The fructification 
lies between these parallel lines. This is most distinctly 
seen when the specimen is sparingly fruited. 
Brake. JPteris, Bags of spores in a long straight line 
covered by the bent-back and rolled-in edge of the leaflets. 
B 
