Ferns 



221 



bacteria, and, what may be still more important, the spores of mosses, 

 fungi, and the seeds of weeds. Thus, when the spores of a desired variety 

 are sown on a sterilized soil, one may assume that the resulting vegetation 

 is fairly clean and true to name. 



According to Hornberger, Ferns generally are made up of 97'292 per 

 cent of organic matter, and 2708 per cent of ash. The latter is made 

 up as follows: 



Iron oxide 0*042 



Potash 0-132 



Soda 0-579 



Magnesia 0-181 



Manganese oxide ... ... ... ... 0*132 



Silica 1-356 



Phosphoric acid 0-121 



Sulphuric acid 0*167 



It will be noticed that lime is apparently non-existent, while silica is the 

 predominating constituent of the ash. Although not absolutely essential 

 for plant growth according to experimental researches, the presence of 

 silica (or flint) in the shape of sand is essential to give that rigidity and 

 firmness to the stems of Fern fronds. 



Sowing- Fern Spores. To secure spores the fertile fronds of any 

 particular species or variety are picked off the plants and placed in thin 

 paper bags and labelled. The bags are hung up in some dry warm spot, 

 and in due course the spores drop out of the cases and form a dark-brown 

 dust within. The spores of all kinds of Ferns are very small and dust- 

 like, hence great care is necessary not to sow too thickly. 



As a rule, 5-in. pots (48's) are most favoured for sowing Fern spores, 

 but other sizes may, of course, be used. The pots are well crocked to secure 

 perfect drainage, and are filled up to within about 1J in. of the top with 

 good fibrous loam. On this a layer of finer and grittier compost, sterilized 

 for preference, is placed, and made fairly firm and level with a piece of 

 flat board. All the pots ready for sowing are prepared thus and then well 

 watered with a fine-rosed watering pot. An hour or two afterwards the 

 spores are sown as thinly as possible over the surface a delicate opera- 

 tion that can only be acquired by practice and a piece of glass is put over 

 each pot. A place shaded from the sun is selected, and attention is given 

 each day to watering. This is best done by plunging each pot into a 

 bucket or tank of water so that the liquid rises from beneath upwards. 

 In applying water overhead there is always a danger of washing the spores 

 to one side of the pot and making ugly holes in the surface. 



Pricking* Off. As soon as the first little true frond or two are seen 

 above the thin semi-translucent prothallus (see p. 213) the young Ferns 

 will be ready for pricking out. For this purpose 5-in. pots, or shallow 

 cutting boxes, are filled with the Fern compost already described, and one, 

 two, or three little plants are lifted with the point of a penknife, or a stick, 

 and gently pressed into the soil. The little plants are afterwards carefully 



