MARCH. 65 



out a small shoot which grows into a minute green plant 

 of very simple structure a mere flat plate of cells. This 

 little organism probably represents a primitive stage of 

 existence through which the ancestral forms of all ferns 

 have passed. It bears two kinds of microscopical cells, 

 male and female, in its tissues, and by the mutual action 

 of two of these an embryo is developed out of which grows 

 a new fern plant. These little rudimentary fern plants 

 may be found in abundance in damp spots in spring-time ; 

 but at this season of the year the only thing to be found is 

 the mature fern plant with its brown clusters of spore 

 cases. 



Ferns are classified by botanists mainly by the position 

 and mode of development of these spore-cases. In the 

 delicate filmy ferns, the fronds of which are only a very 

 few cells thick, the tips of the fine divisions of the blades 

 divide into a sort of flap, inside of which stands the little 

 brown cluster of spore-cases. In common bracken and its 

 allies the edges of the fronds are folded back and the spor- 

 angia lie in rows inside the folds ; while in the Polypodies, 

 such as the common climbing form that is so abundant on 

 tree trunks, they are grouped in rounded clusters on the 

 backs of the fronds. These are only a few of the arrange- 

 ments which occur. 



When a spore-case is ripe it is burst open by the 

 shortening of an elastic band at the back, and numerous 

 little spores are cast forth. Where ferns, especially 

 bracken, are very abundant, as on the lower hills round 

 the great southern lakes,* the scattering of the spores 

 occasionally produces curious effects. The fine dust is 

 so difficult to wet that it gathers on the surface of the 

 lakes in a thin film which glistens in sunlight like a sheet 

 of burnished copper, and in shadow gives a deep red-brown 

 hue to the water. When several square miles of lake 

 surface are thus transformed in the sloping rays of the sun 

 the effect is said to be very remarkable and almost awe- 

 inspiring. I have not myself seen this phenomenon on a 

 large scale. 



* Lakes Wakatipu, Te Anau, and Manapouri. 



