16 PERNS OF GEE AT BRITAIN. 



mid-rib, not uniting with the adjoining lobe. Name 

 from M. De Lastre, of Chatelleraut. 



6. PoLysTicHUM. — Clusters seated at the back of the 

 frond, covered by a circular indusium, attached at its 

 centre. Name from the Greek, poly, many ; and stichos, 

 a row ; from the regular lines formed by the clusters of 

 fructification. 



7. CrsTOPTEuis (Bladder Fern). — Clusters of fructifi- 

 cation roundish ; indusium hooded, and attached by its 

 broad base. Name from the Greek, hystos, a bladder ; 

 and pteris, a fern ; in allusion to its hollow indusium. 



8. Athybium. — Clusters at the back of the frond, 

 covered with a kidney-shaped or crescent-shaped indu- 

 sium, attached along the upper side of the lateral veins, 

 opening towards the mid-vein, its margin fringed with 

 slender hair-hke segments. Name from the Greek, 

 athyros, open ; because the indusium stands out sepa- 

 rated from the frond, and is at length turned back open 

 from it, 



9. AsPLENiTJM (Spleenwort). — Clusters at the back of 

 the frond, oblong or linear, attached along the upper or 

 inner side of the veins j indusium opening toward the 

 mid-vein, or inwardly. Name from the Greek asplenon, 

 given by the ancients to some fern which they believed 

 to affect the spleen. 



10. ScoLOPENDRiuM (Hart's-tougue). — Clusters on 

 the back of the frond, long, narrow, straight, and in 

 pairs; indusium double; the two portions opening 

 towards each other. Name from Scolopendra, a cen- 

 tipede, from a fancied similarity between the lines of 

 fructification and the feet of that animal. 



