PROPAGATION BY MEANS OF SEEDS AND SPORES 13 



and sandy loam which is set inside a larger pot, the inter- 

 mediate space being filled with moss, to which, alone, the water 

 is applied. This device is illustrated in Fig. 3. The water 

 soaks through the walls of the inner pot and is supplied gradu- 

 ally and constantly to the soil. Even in this case it is necessary 

 to prevent soaking the moss too heavily, especially with very 

 weak seeds. When many pots are required, they may be 

 plunged in moss with the same effect. The soil should be only 

 very slightly moist, 

 never wet. Mois- 

 ture is sometimes 

 supplied by setting 

 the seed-pot in a 

 shallow saucer of 

 water, or it may be 

 sufficient to place it 

 in the humid atmos- 

 phere of a propa- 

 ga ting-box. Large 

 but weak seeds may 

 be laid on the surface of the soil in a half-filled pot, covered 

 with thin muslin and covered again with loose and damp loam. 

 Every day the pot is inspected, the covering taken off and 

 fresh soil added. A modification of this plan, for small seeds, 

 is made by placing the seeds between two layers of thin muslin 

 and laying them in damp loam,- which is frequently renewed 

 to avoid the extremes that would result from watering or from 

 allowing the soil to become dry. In these last operations, 

 no water is applied to the seed, and they constitute one of 

 the most satisfactory methods of dealing with seeds of low 

 viability. They are essentially the methods long ago used by 

 Thomas Andrew Knight, who laid such seeds between two sods 

 cut from an old and dry pasture. 



Seeds of orchids and certain other plants are sometimes 



FIG. 3. Double seed-pot, with moss between the 

 two pots; also a block of wood on which certain 

 seeds may be sown. 



