PILICES. 175 



5. Asple'ninm. Fruit-dots elongated, on veins on the back of the 

 pinnules, oblique to the midrib, but only on the upper side of th> 

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

 free. 



U. \Voodwardia. Fruit-dots elongated, on cross-veins parallel to the 

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

 as in the last. Veins reticulated. 



7. Scolopeii'drium. Fruit-dots elongated, occurring in pairs on contiju- 



ous 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, gener- 

 ally wavy-margined. 



8. Camptoso'rus. Fruit-dots elongated, those near the base of the midrib 



double, as in Scolopendrium ; others single, as in Aspleniuin. Fronds 

 simple, J or | 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. Pliegop'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. Aspid'ium. Fruit-dots round. Indusium evident, flat, orbicular or 



kidney-shaped, fixed by the centre, opening all round the margin. 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 tht; 

 side towards the apex of the pinnule, and becoming reflexed as the 

 sporangia ripen. Fronds slender and delicate, twice- or thrice- pinnate. 



12. Struthiop'teris. Fertile frond much contracted and altogether unlike 



the sterile ones, the latter very large and growing in a cluster with the 

 shorter fertile one in the centre. Rootstock very thick and scaly. 

 Fertile fronds simply pinnate, the margins of the pinnae rolled back- 

 wards 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, 



260, and accompanying description.) 



14. Dickso'nia. Fruit-dots round, very small, each on a recurved toothlet 



on the upper margin of the lobes of the pinnules, usually one to each 

 lobe- Sporangia on an elevated globular receptacle, and enclosed in a 

 cup-shaped indusium open at the top and partly adherent to the reflexed 

 toothlet of the frond. Fronds minutely glandular and hairy, 2-3 feet 

 high, ovate-lanceolate in outline, pale green, very thin, without chaff. 



