DEVELOPMENT ON A FERN. 
45 
The development of the fern from the spore may be 
watched thus:— 
Choose a frond with ripe spores, place it between drying 
paper for a day or two, and then shake it over prepared soil. 
Shaking is preferable to scraping unless you are trying to 
porduce new varieties; in that case the spores should be sown 
as thickly as possible. By “prepared soil” is meant soil that 
has been either roasted or scalded in order to destroy all 
vegetable or animal germs that may be in it. Shallow pans 
should be used half filled with bits of broken pot to ensure 
good drainage, and the surface of the soil should be made 
smooth by gentle pressure. 
The spores should not at first be watered directly, but the 
pots should either stand in water (distilled or boiled), or be 
plunged in water once a day for a few seconds. 
For more convenient observation the spores may be sown 
on glass or on a bit of pot; the former is rather a tedious 
process. 
The spore, like all true spores, will germinate from any 
point of its surface indifferently. 
All spores do not germinate equally soon, spores from 
Osmunda germinating much sooner than others. 
Usually the spore gives rise first to a long slender filament 
the terminal cell of which divides and sub-divides into a flat 
leaf-like and usually kidney-shaped expansion termed the 
prothallium, but in the case of Osmunda the pro thallium is 
formed at once, and there is no long filament. 
Scattered round the margin of the prothallium and on 
the under side are the antheridia, which are minute cellular 
sacs usually stalked—(I have even seen them on the stem of 
the young fern)—whilst on the under surface just behind the 
indented portion are the archegonia, which are bottle-shaped 
organs, buried in the substance of the “cushion,” as this 
part is called, because here the protliallium consists of several 
layers of cells, instead of a single layer, as it does nearer the 
margin. 
The protliallium shows a decided dioecious tendency. 
Sometimes from a whole sporangium all the prothallia 
developed will bear antheridia only ; in others the archegonia 
appear later, to be fertilised by antheridia from younger 
prothallia. 
Under certain conditions a protliallium will produce pro¬ 
thallia by gemmae, and will sometimes, though rarely, 
produce the new fern by a process of budding. 
The antheridia which contain the sperm or antherozoid 
cells are protected by a wall of thin cells. 
