THE LIFE OF A FERN. 



their vitality for several years, as it has been found 

 possible to develop plants from the spores of her- 

 barium specimens. After the spores have been 

 placed in some suitable receptacle for a few days, 

 or perhaps weeks, a greenish scum will be noticed 

 covering the damp surface on which they have 

 been sown. This is the first stage of fern growth. 

 It occurs thus : The outer cell-wall (exospore) is rup- 

 tured by the moisture, and the cell-contents (endo- 

 spore) protrude, and begin to divide, the division 

 forming new cells, which join themselves to the 

 first. A continuance of this process gives rise, 

 successively, to the various forms shown in PI. 

 3, Figs. 5-9, until bodies are produced which 

 are shown highly magnified in Figs. 10-14. 

 These little shield-shaped structures grow very 

 thickly together, and are attached to the earth, 

 or whatever substance they have taken to ger- 

 minate upon, by root hairs, not true roots. 

 They rest at such an angle here, that they be- 

 come imbricated, and, except that they are some- 

 what more erect, resemble in this arrangement 

 the scales on a butterfly's wing, or the slates upon 

 a roof. The prothallus, as each of these bodies 

 is called, is composed of cells containing grains of 

 chlorophyll, which gives the whole its green color. 

 On the prothallus, projecting from the under side, 

 are the organs which are analogous to the stamens 

 and pistils of flowering plants. They are, I. The 



