Decline of Growth and the Rest Period. 109 



the layers may be built up in a pile on the ground. The 

 sand should be coarse enough to admit some passage of air 

 between the particles and to give perfect drainage. The 

 layers should not much exceed an inch in thickness, ex- 

 cept for the larger seeds, and the number of layers should 

 not be so large as to prevent proper aeration of the mass. 

 Small ciuantities of seeds may be mixed with sand or 

 porous loam in flower-pots. Moisture may be maintained 

 in the boxes or pots by burying them a foot or more deep 

 in the soil in a -nell-drained place, or liy storing them in 

 a moist cellar. Care is necessary to keep mice and other 

 vermin from stratified seeds. It is well to cover pots in 

 which valuable seeds are stratified, with a sheet of tin 

 or zinc; metal labels are best for distinguishing different 

 sorts of seed. The seeds should remain stratified until 

 sowing time, when they may be sifted out of the sand or 

 S(n^-n with it, as is more convenient. Seeds that do not 

 germinate well until the second spring after maturity 

 .(163) are commonly left in stratification until that time. 



Sectkjx XIII. Th]-: Decline of Groavth and the 

 Ee«t Period 



171. Annual plants usually perish soon after maturing 

 their seed. In other plants, a certain period of vital 

 acti\'ity is followed by one in which growth gradually 

 declines until it almost or entirely ceases. In woody 

 plants, the cells become thickened and a part of the rudi- 

 mentary leaves change to bud-scales, which inclose the 

 growing point (128). In deciduous (de-cid'-u-ous)* trees 

 and shrubs, the chlorophyll and starch, with most of the 



* Deciduous trees and shrubs are those of which the leaves perish at 

 the beginning of the rest period. 



