FERTILISATION AND PROPAGATION. 



121 



the seedlings have formed a little crown, watering should always be done by 

 partial immersion — that is, by allowing the lower part of the pots to stand in 

 water till sufficient moisture has been absorbed — but the pots should not in 

 any case remain altogether in water. To that effect, they should be stood in 

 saucers, and disposed in places varying in temperature according to the nature 

 of the species sown. 



Beginning with British and other hardy kinds, we find that, although 

 they germinate more rapidly, and also take less time in producing young 

 characterised plants, when sown in heat, it is not at all necessary to have any 

 artificially -heated place in which to sow and grow them. In their case, the 

 pots or pans may be placed in some damp, shady, but not dark corner, out 

 of the way — under the stage of a greenhouse, if such a j)lace be available, is 

 a good situation for them ; and it is necessary to stand them on a piece of 

 slate, or by other means to prevent the worms from getting in from below. 

 There, without further attention, they should remain, until the surface of the 

 pots or pans becomes covered with a growth of Lichen or Liverwort appearance ; 

 from this the young plants ultimately develop, according to the different 

 species, in a space of time usually varying from three to six months from 

 the time of sowing. A certain state of apparent dormancy, lasting sometimes 

 several weeks, may be observed between the production of the scaly growth, 

 and the sudden appearance, here and there, and eventually in a crowd, of the 

 fronds proper, and it is during that period that the reproductive functions 

 previously described take place ; it is also principally during that time that, 

 to encourage fertilisation, a uniform rate of moisture is of the greatest 

 consequence. 



When Fern spores germinate freely, and form a dense mass of prothalli, 

 it is necessary, or even indispensable, that they should be several times divided 

 —a delicate operation known as "pricking off," the effect of which is to give 

 them room to develop themselves ; for, if allowed to crowd and overgrow 

 each other in the seed-pan, they are very liable to clamp off. The " pricking 

 off" consists in taking small tufts of prothalli, and putting them in pots 

 filled with a material similar to the one in which they have been sown ; but 

 great care must be taken that -no bruises result from that operation, and, on 

 that account, small patches should be taken on a stick having the least notch 

 cut in the end, and they should be merely deposited, not pressed, into the 



