— 5°- 



opposite margins are so characteristic that the merest 

 novice has no trouble to refer all ordinary forms to their 

 proper places. More difficulty would be experienced, 

 however, if all the ferns of the world were examined, 

 for then it would be seen that all maiden-hair ferns do 

 not have pinnules of the one-sided type and we should 

 have to fall back on the characters of the sorus and in- 

 dusium to be sure of our plants. The species that we 

 have chosen for illustration is one ' of the latter kind. 

 From a casual glance at its fronds we would scarcely 

 take it for a fern at all, much less a maiden-hair fern, 

 but the characteristic form of the fruit dots settles the 

 question beyond doubt. It may be added, however, that 

 maiden-hair ferns with simple entire fronds are exceed- 

 ingly rare, there being only one other species with this 

 peculiarity in the world. Both are natives of the Old 

 World, Adiantum reniforme being found in Madeira and 

 Teneriffe and A. Parishii growing in the Malay Penin- 

 sula. Our illustration of A. reniforme is_ nearly life size. 

 A. Parishii has much shorter stipes. 



The genus which Adiantum is nearest like is the Tropi- 

 cal one called Lindsaya. The latter has one-sided pin- 

 nules as ki the maiden-hair family and its sori are mar- 

 ginal. The indusium, however, is slightly different, hav- 

 ing an inner membraneous indusium and an outer thicker 

 one formed by the reflexed part of the frond. The 

 sporangia, moreover, are situated on the frond at a slight 

 distance from the margin in Lindsaya, while in Adian- 

 tum the sporangia grow from the reflexed lobes that 

 form the indusium. Some tropical forms of maiden-hair 

 have elongated sori that might incline one to think them 

 members of the Pteris genus, but in this latter the 

 sporangia are in a continuous marginal sorus and covered 

 by the reflexed edge of the frond. 



