i 



258 COMMOtf CANADIAN WILD 



5. Asple' ilium. Fruit-dots elongated (rarely curved), on veins on the 



back of the pinnules, oblique to the midrib, but only on the upper 

 side of the vein ( rarely attached to both sides). Indusium attached 

 to the vein by one edge, the other edge free. Veins free. 



6. Wood war' <l in. Fruit-dots elongated, on cross-veins parallel to the 



midrib, forming a chain-like row on each side of the latter. In- 

 dusium as in the last. Veins reticulated. 



7. Scot open <lrin in. Fruit-dots elongated, occurring in pairs on con- 



tiguous veinlets, the free edges of the two indusia facing each 

 other, so that the sori appear to be single, with an indusium split 

 down the centre. Veins free. Frond simple, ribbon- shaped, about 

 an inch broad, generally wavy-margined. 



8. Camptoso'rns. Fruit elongated, those near the base of thejnidrib 



double, as in Scolopendrium ; others single, as in Asplenium. 

 Fronds simple, J to } of an inch wide at the heart-shaped base, 

 and tapering into a long and narrow point ; growing in tufts on 

 limestone rocks, and commonly rooting at the tip of the frond, 

 like a runner. Veins reticulated. 



9. Phegop'teris. Fruit-dots roundish, on the back (not at the apex) of 



the veinlet, rather small. Indusium obsolete or none. Veins free. 

 Fronds triangular in outline, in one species twice-pinnatifid, with 

 a winged rhachis, and in the other in three petioled spreading 

 divisions, the divisions once- or twice-pinnate. 



10. Aapld lum. Fruit-dots round. Indusium evident, flat, orbicular 



or kidney-shaped, fixed by the centre, opening all round the mar- 

 gin. Veins free. Generally rather large Ferns, from once- to 

 thrice-pinnate. (See Fig. 264.) 



11. Cystop'teris. Fruit-dots round. Indusium not depressed in the 



centre, but rather raised, attached to the frond not by the centre, 

 but by the edge partly under the fruit-dot, and generally breaking 

 away on the side towards the apex of the pinnule, and becoming 

 reflexed as the sporangia ripen. Fronds slender and delicate, 

 twice- or thrice-pinnate. 



12. striilliio]* Icris. Fertile frond much contracted and altogether 



unlike the sterile ones, the latter very large and gi-owing in a 

 cluster with the shorter fertile one in the centre. Rootstock very 

 thick and scaly. Fertile fronds simply pinnate, the margins of 

 the pinnse rolled backward so as to form a hollow tube containing 

 the crowded sporangia. Very common in low grounds. 



13. Onocle'a. Fertile and sterile fronds unlike. (See Figs. 266, 267, 



268, 269, and accompanying description. ) 



14. Wood *i:i. Small ferns with free veins. Sori round. Indusium 



very thin and delicate, attached by its base all round under the 

 sorus, the top at length bursting into more or less narrow see- 

 ments. 



