FACTORS DETERMINING CHARACTER AND DISTRI- 
BUTION OF FOOD RESERVE IN WOODY PLANTS 
EDMUND W. SINNOTT 
(WITH TWO FIGURES) 
Introduction 
The investigations of Russow, FiscHer, and others upon the 
character and seasonal changes of the food reserves in woody plants, 
and the considerable attention which this problem has more recently 
received, have made us familiar with many of the important facts 
which it involves; but as to the underlying causes which determine 
the type of reserve food occurring in any cell and which direct its 
changes i in form and location we are still uncertain. Our present 
knowledge, derived in greater part from a study of twigs, branches, 
and small trunks and roots, may be summarized substantially as 
follows. The major part of the reserves stored up by trees and 
shrubs during the productive season is evidently composed of 
starch (fat is also demonstrable, and SaBLon (5) has emphasized 
the importance of reserve cellulose as a center of storage). At 
about the beginning of winter there is a decided reduction in the 
amount of starch, leading to its disappearance in the phloem 
and cortex of practically all woody plants in our latitude. At 
the same time the amount of fat seems to increase greatly. In 
certain forms, called by FiscHEr (2) “‘starch trees,’ there is no 
further change, the food reserves in the pith and wood persisting 
in the form of starch throughout the winter. In others, called by 
him ‘‘fat trees,” the starch vanishes in these portions of the stem 
as well, and fat appears in abundance, constituting the only visible 
food reserve during the winter. In all woody plants, late winter 
or early spring sees a regeneration of starch throughout the tissues 
of the stem and an apparent diminution in the amount of fat. 
This regenerated starch is used up in the formation of the spring 
growth, and it is not until summer that a fresh supply begins to be 
deposited. It has been supposed that at the seasonal changes 
Botanical Gazette, vol. 66] [162 
