GHAPTER XL 



VIVIPAROUS AND PROLIFEROUS FERNS. 



HESE form a very numerous and important group, comprising 

 plants of many genera, some of which, such as Gymnogramme, 

 Polypodium, Pteris, Cystopteris, &c, have among them only 

 one, or perhaps two, species partaking, as if accidentally, of 

 the above-named characters ; whereas others, and principally 

 Asplenium and Woodwardia, are particularly noted for the quantity of viviparous 

 and proliferous sorts which they comprise. There are several distinct ways 

 in which these singular characters are shown in Ferns. In some instances, 

 such as the popular Asplenium bulbiferum, A. viviparum, the handsome Japanese 

 Nephrodium prolificum, &c, the upper surface only of the foliaged portion of 

 the fronds is wholly or partially covered with adventitious growth ; or again, as 

 in the case of Cystopteris bulbifera, with numerous small bulbils which answer 

 the same purpose of reproduction. In others, such as Aspidium (Polystichum) 

 angular e proliferum, the proliferous characters, instead of being present on 

 the foliaged part of the frond, are entirely restricted to the stalk or rachis ; 

 there they are crowded together, and form a perfect mass of young growth 

 which, when left to its own resources, seldom attains any particular dimen- 

 sions. In other cases, again, such as some of the Adiantums, Aspidiums, &c, 

 the fronds bear (generally at their apex) one solitary bulbil, or produce, as a 

 prolongation to the midrib of their fronds, a young plant which, in its turn, 

 develops into a full-grown subject, and from the extremities of the fronds of 

 which another generation of plants is produced. Then there are Ferns which 

 are proliferous through latent buds being disposed on the stalks, usually at 



