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MANUAL OF NATURE STUDY. 
branch, of cherry, peach, sycamore, bean. Have 
pupils count the rings of growth in stumps of trees 
and cross sawed timber. Do these rings represent 
periods of growth ? Can we then form some notion 
of the age of the tree? By way of contrast, make 
a collection and study of endogens. As in exogens 
collect bundles of cuttings three or four inches long. 
Examine cross sections to see if the bark is the same 
as that which covered the exogens. Can you in 
any way pound or rub the bark of a cornstalk loose 
as you did the willow bark? Can you the grass 
bark? The wheat bark? Sugar cane? The 
palm? Pond weed? Cat tail? Indian turnip? 
Banana ? Lily ? Pineapple ? Any of the rushes ? 
Fish pole ? Do you find in any of these cuttings 
the fibre bundles arranged in rings around a cen¬ 
tral pith ? Compare with oak, box-elder or bean in 
this respect. Make drawings of cross sections of 
endogens, alternated with exogens so as to get the 
distinction fully fixed on the mind. Plant a few 
acorns, beans, peas, beech nuts in same dirt 
with corn, sugar cane, wheat, and notice difference 
in number of seed leaves as they begin to come 
through the dirt. Those having two seed leaves 
are called dicotyledonous plants, and those having 
but one seed leaf monocotyledonous. To which of 
these does corn belong? Apple? Is the walnut 
exogenous or endogenous? How can you tell? 
