THE LIFE OF A FERN. 



15 



illustrated by the Zoospores or swarm-spores of 

 the lower Algce^ as in Conferva, the common 

 green scum seen in stagnant water ; or the tetra- 

 spores of the Floridece, seaweeds of a higher grade. 

 The gemm<2 of the HepaticcB and Mosses represent 

 the same thing : in these the little seed-like buds 

 are scattered, and reproduce the species which 

 bore them, without any fertilization whatever. 

 The Lycopodiitms supply instances of this same 

 phenomenon, and it is of quite common occur- 

 rence among flowering plants. Illustrations are 

 found in Begonia and Bryopkylhtm, and particu- 

 larly in the familiar bulblets of the Tiger-Lily, 

 which are found at the base of each leaf, and are 

 to be considered as detached axillary buds con- 

 densed in form as they are separated from the 

 plant. 



A farinaceous substance, white or yellow, is 

 sometimes developed on the under side of some 

 ferns, and, in one or two varieties, on the other 

 side also. It is often thick enough to cover and 

 hide the fruit. This gives the popular names 

 "Gold" and ''Silver" ferns to such species. It 

 occurs most frequently with Gymnogramme and 

 Notholcena (see PI. 2). Occasionally upon the 

 same plant of G. calomelanos will be found some 

 fronds with white, and others with yellow farina. 

 All plants of this habit should be carefully kept 

 out of the way of dripping water, and should not 



