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. Asplenium bulhiferum (see fig. 200) develop 

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

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

 in the East Indies, it is fi-om the little stalks of the ultimate green lobes, in 



Fig. 199.— Formation of Buds on tlie apices of tlie Fiunds of Ferns : Aupknium Edjewuiiln 



Gleichenia from the angles of the forkings of the fronds (c/. fig. 189"), and in 

 Asplenium 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 lio-ht, in other words, they bend towards the darkest parts of tlieir 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 



