ON FERNS. 551 



burned or scalded to destroy all germs of vegetable life and all 

 insects that may be found in them. When ready for sowing, 

 the pots or pans should not be quite full; the top layer should 

 not reach the outside surface of the pot by about ^in., as it is 

 necessary that they should be covered with a piece of glass, 

 ■which should remain on them until the young seedlings are up, 

 and the space thus reserved is required for their development. 

 The pots or pans should then be stood nearly to the rim in 

 water, in which they should remain long enough to get 

 thoroughly soaked, after which they should be allowed to drain 

 for a few minutes, when sowing may take place. 



On account of their extreme minuteness, the spores, when sown, 

 must not be covered with soil ; they should be simply scattered 

 thinly over the surface of the compost contained in the pots or 

 pans, which should immediately be covered with a piece of glass. 

 This has for its object the total exclusion of other spores which 

 may be in suspense about the place, and it also greatly helps 

 to keep a close, moist atmosphere about the spores which, on 

 that account, germinate and grow more freely than they would 

 do if left uncovered. It is also necessary, while sowing, to hold 

 the paper which contains the spores very close to the surface of 

 the pots or pans, and care should be taken that the operation is 

 performed in a perfectly still atmosphere, as, being of an 

 exceedingly light nature, they are very liable, under the influence 

 of the slightest draught, to fly in all directions. When the 

 sowing has taken place, it is advisable to stand the pots 

 or pans, covered with glass, in shallow saucers containing water, 

 which will rise to the compost and keep' it in a uniform state 

 of moisture; they should then be disposed in places varying in 

 temperature with the species sown. 



Watering of Spores. — The watering of the pots or pans in 

 which the spores have been sown is an operation requiring 

 great attention, as it is at a certain given time, and through the 

 agency of moisture, that their fecundation takes place. Should 

 the water in the saucers prove insufficient to keep the soil moist, 

 the pots must be watered by partial immersion, that is by 

 allowing the lower part to stand in water until sufficient moisture 

 has been absorbed to soak the mass of soil. 



The length of time which elapses between the sowing of 

 the spores and their germination is very variable, some showing 

 signs of life in the course of a few days, while others are 

 sometimes several months before doing so. It has been 

 observed that even those taken from one frond sometimes 

 vary in the length of time they take to germinate, some of 

 them developing weeks before others, although sown at the 

 same time, subjected to the same treatment, and even when 

 sown in the same pan. The germination of the spores is 

 clearly indicated by a faint colouring of green on the surface 



