Propagation by Division. 177 
d. Seeds should be planted no deeper than is necessary to 
insure the proper degree of moisture ; otherwise, the plantlet 
expends needless energy in reaching the surface (48). Very 
small seeds should be only slightly covered, if at all, and 
must receive artificial watering, if necessary (52). Spores 
must not be covered with soil at all (53). 
B— PropaGaTION BY DIVISION 
345. We have seen (340) that a part of a plant, placed 
under favorable conditions, is usually capable of developing 
into a complete plant. A section or cutting of the stem, for 
example, that has no roots at the time it is cut off, may 
often be caused to form roots, and thus become a complete 
plant. A cutting of a root may, in many cases put forth a 
bud, which in turn may develop into a shoot, and form 
leaves, flowers and fruit. Again, we have seen (70) that 
portions of cambium from different, nearly-related plants 
may unite by growth, which enables us to change undesir- 
able seedlings into valuable sorts by grafting (383). These, 
and certain other methods of multiplying plants, come under 
propagation by division. 
In propagation by division, the presence of at least one healthy 
growing point on the part selected for the propagation is gener- 
ally essential to success and is always helpful. 
346. Two Methods of Propagation by Division may 
be distinguished, viz., by parts intact, and by detached parts. 
In the first, the part selected for propagation is not sepa- 
rated from the parent until the organs needed to make it 
self-supporting are formed; or if a cion (383), until it has 
united to the part on which it is intended to grow. In the 
second method, the part intended for propagation is severed 
from the parent at the outset, and plaved under conditions 
