946 THE BOOK OF GARDENING. 



sown on cocoanut-fibre in the frame of a propagating-house. 

 Pots would answer quite as well as pans or boxes for small 

 seeds, only they have the disadvantage of taking up too much 

 room ; but they are often used for Fern spores, and for some 

 classes of plants when seeds are sown in small quantities. 



Natural Sowing. — This kind of sowing is, of course, going 

 on all over the earth. We may take for example the way in 

 which a quantity of our British trees, shrubs, and other plants 

 propagate themselves ; and it is exactly the same with tropical 

 and sub-tropical subjects in their native countries. The seeds 

 when ripe drop to the ground, and when they find the con- 

 ditions required they germinate and grow where they fall. 

 It is also curious to note that many tropical and sub-tropical 

 plants reproduce themselves in the same way in our houses, 

 and some very striking examples might be mentioned. Take 

 for instance a multitude of Fern spores which have been sown 

 in pans in a most careful manner. Often it will be noticed that 

 during the operation of sowing, spores get blown off, and germinate 

 at the. other end of the house, growing on the brick wall where 

 moisture is permanent. In nurseries where Ferns are grown in 

 considerable quantities, attention is always given to spores which 

 germinate on walls or elsewhere. 



Orchids are also prone to sowing themselves ; indeed, this is 

 mostly found with very light seeds or spores. Orchids are gene- 

 rally sown on the top of the compost of some other plants, as 

 their seeds are so fine that the least action of air will easily 

 blow them away, and, they have several times been found 

 .germinating and growing along a wall or on woodwork. A most 

 peculiar example of this is shown in the Orchid collection at 

 Burford Bridge, where a splendid specimen of Vanda Sanderiana 

 may be seen with a colony of Orchid seedlings growing on its 

 roots. These instances serve to show us how little practically 

 we at present know about the natural conditions under which 

 tropical and sub-tropical plants grow. 



Aquatics are mostly and successfully sown in water, e.g., 

 Victoria regia, numerous Nymphasas, and many others. The 

 seeds should be sown in pans or pots, with a mixture of fibrous 

 loam, leaf-mould, and sand, and the receptacles covered and 

 placed in the tank of the house a few inches below the water 

 level, and kept at an average temperature of 8odeg. As soon 

 as the plants commence to gr'ow they may be transplanted in 

 pots separately. They must always be kept under water; and as 

 the plants grow the level of the water must be gradually raised, 

 or the plants sunk, so as to enable them to float on the surface. 



Hot-beds. — It is not always necessary to have a propagating- 

 house, as many plants may be raised in frames containing a hot-bed, 

 the bottom of which must be composed of fermenting matter, such 



