os i = ee 
100 ABOUT A FERN. [CHAP. 
a pale brown colour, composed of cells, one row of 
which has thicker walls than the rest, and thus forms 
a band round the edge of the case. This case is 
botanically termed a sporange (fig.95, 4), and the clus- 
ters of them are spoken of as sorz, They contain the 
exceedingly minute spores, which are visible to the 
naked eye merely as a fine dust. When these spores 
are ripe their increased size exerts such pressure 
upon the sporange that the elastic ring of cells is 
ruptured and extended out straight; a transverse 
split occurs in the sporange, and the spores are scat- 
tered by the violence of the rupture (¢). We shall in 
all probability observe this taking place among those 
under our microscope. Suppose that these spores are 
scattered in their natural habitat, say upon some damp 
mossy stone, or hedge-bank in a sheltered spot, where 
there is thorough moisture. They germinate. First 
a little tubular process shoots out from the spore (fig. 
96, 6), and from the under side of that another similar 
process is developed and becomes the first rootlet. The 
tubular process from which it was developed divides 
into cells, which again divide and subdivide, until they 
form a tiny kidney-shaped green disc which gives off 
from its under surface very minute fibres which attach 
it to the soil. This little flat green expansion is known 
as a prothallus (ad). On its under surface it gives rise 
to the reproductive organs, which are known only by 
theirscientificnames. Theyare of two kinds, and ana- 
logous to the stamens and pistil of flowering plants. 
The first of these is called the antheridia (d, 2), and 
are found among the rootlets; the second is known as 
the archegonia (d, 4), and are produced on a thickened 
