IMPORTANT FLORISTS' PLANTS 



147 



Fig. 81. Ferns. 1, A Fern plant bearing a mature and an unfolding frond (c). Each 

 division of the frond (or leaf) is known as a pinna (plural, pinnae) (P). The pinnae 

 are covered with dot-like masses, or spore cases (sp). The underground stem of a Fern 

 is known as a rhizome or root-stock (R). 2, A portion of a frond of Osmunda regalis, 

 the Royal Fern; in this case certain pinnae are much reduced in size (sp.) and are the 

 only ones which bear the spores. 3, A Fern prothallus. This is the sexual stage and 

 produces the male and female organs which in uniting give rise to the growth of the 

 mature forms. This prothallus has started to produce a frond (See page 146) 



Sowing Fern spores. The pots used should be thoroughly'sterilized 

 by burning. When large quantities of Ferns are grown the spores 

 are sown in flats or shallow boxes, although usually seed pans will be 

 large enough. Plenty of drainage (broken flower pots) is always used 

 in the bottom of the flats. The soil is now carefully placed in the flat 

 and lightly pressed to a perfect level. If the surface is not absolutely 

 level the lower portions of the flat will become damp and sour. Water 

 the soil with a fine rose spray, or submerge the flat in water so that 

 there will be sub-irrigation. Scatter the spores evenly over the surface 

 after the soil has lost its first appearance of wetness, and cover with a 

 pane of glass and a newspaper. When the spores have germinated 

 the glass should be raised to give ventilation. Gradually more air 

 should be given until finally the glass may be removed. 



