BUDS ON LEAVES. 



39 



conveniently introduced until we come to the description of Ferns themselves. 

 It is sufficient to mention here that buds very frequently occur on the fronds 

 of Ferns; indeed, certain species, e.g. Asjdenium bulbiferum (see fig. 200) develop 

 buds on almost all their fronds. In most cases they spring from the surface of 

 the green pinnre, but in Ceratopteris thalictroides, a common denizen of swamps 

 in the East Indies, it is from the little stalks of the ultimate green lobes, in 



Fig 199 — Foimation of Buds on the apices of tlie Fionds of Feins Aipleniuiii EdjeuoiUu 



Gleichenia from the angles of the forkings of the fronds (cf. fig. 189^), and in 

 AspleniuTYi Edgeworthii (see fig. 199), from the apices of the fronds, that is to say 

 from the extremities of the cladodes. The last-mentioned Fern grows upon the 

 bark of trees, and the tips of its fronds are endowed with the property of avoiding 

 the light, in other words, they bend towards the darkest parts of their substratum, 

 creeping into the fissures in the bark, where they become firmly adnate, and each 

 develops a bud above the point of contact. This bud gives rise once more to 

 fronds, of which, however, one only, as a rule, develops vigorously. After it has 

 unrolled itself, this new frond in turn searches with its apex for a dark rift. The 



