148 



PRACTICAL PLANT PROPAGATION 



When the Ferns have grown several leaves they should be trans- 

 planted on the point of a knife into flats, using a soil consisting of a 

 mixture of leaf mold and sand. 



Hybridizing Ferns. It is when the Ferns have grown to resemble 

 a small round leaf that they have reached the prothallus stage or sexual 

 period (see fig. 8 1 3 ). They will now hybridize. If hybrids are not 

 wanted, keep the various flats away from each other, otherwise a mixed 

 lot of stock will result. Ferns do not mix when in the large, frond- 

 bearing stage. It is not the spores of the fronds which do the crossing. 



Fig. 82. Ferns. 1, A microscopic view of a spore case before it has burst. 2, The 

 spore case has ripened and is scattering its spores. 3, The spore areas of Adiantum. 

 Note that the tips of the pinnae are folded back and it is under the margins that the 

 spore cases are produced. 4, The spore cases form huge clusters in Polypodium. 5, 

 In Dryopteris the spore cases are kidney-shaped. 6, Each pinna at the tips of certain 

 fronds of Pteris has the edged rolled back; under these the spore cases are borne 



(See page 146) 



When hybridization is desired sow the various sorts of spores to- 

 gether, so that when the sexual stage develops, the plants may cross 

 one with another. 



Propagation by division. Many Ferns produce prominent rhizomes 

 which may be cut into small pieces and placed in the propagating 

 bench, with a little bottom heat, to root. When rooted they should 

 be potted into small pots, using a loose soil. A decayed sod loam and 

 leaf mold mixture will be best. A few of the Ferns so propagated are: 

 Adiantum; DavaUia, the Rabbit's Foot Fern; Dicksonia; Lygodium, 

 the Climbing Fern; Nephrolepis, the Boston Fern allies; Osmunda; 

 Phlebodium; Polypodium; and Niphobolus, also called Cyclophorus. 



