FERN GROWING 169 



feet deep ; this pit is covered with glass, which is only lifted 

 for the purpose of watering, nevertheless it is crowded with 

 seedling Ferns. 



If a collection is to embrace all the British species, there 

 should be a greenhouse, the span-roof house is the best (with 

 ventilation along the ridge), as in Messrs. Foster & Pearson's 

 houses ; the walk should be in the middle with a border of 

 6 feet to 8 feet on either side. There should be a wall on 

 either side of 3 feet high, and the borders should be raised to 

 this height, in which the plants can be plunged in their pots, and 

 the glass roof should be covered with what is known as the 

 Willesden scrim shade, which, although a perfect shade, does 

 not make the house too dark. There are some delicate fronded 

 Ferns such as Acrocladon, Clarissima, and Kalothrix varieties 

 of the Asplenium Fzlix-fcemina, Aspidium Lonchitis, &c., that 

 grow much more satisfactorily than in the open Fernery. Some 

 Ferns, as the Adiantum Capillus- Veneris, and Asplenium mari- 

 num, require heat in winter. 



We have elsewhere alluded to a Filmy Fern-pit. But there 

 is yet another structure (in which young plants may be planted 

 in lines to strengthen) which is extremely useful : it is a frame 

 with a brick or wood side on the south, and lean-to lights 

 on the north side ; the lights should be 3 feet at the back, 

 and I foot at the front, and within should be at least 6 inches 

 of good soil in which the Ferns should be planted ; the glass 

 should be in separate lights of 3 feet in length, for easy 

 movement, and should rest against uprights to prevent their 

 being blown off by the wind. 



There are great differences in the time occupied in the 

 germination of spores, some species taking much longer than 

 others ; freshly gathered spores occupying the least time, 

 and those that have been kept for a number of years ger- 

 minating the slowest. After pricking out the seedlings, if 

 the pans are kept, further seedlings will spring up, and these 



