VOLUME XXIV NUMBER 5 
BOTANICAL (GAZETTE 
5 NOVEMBER 1897 
COMPARATIVE ANATOMY OF THE NORMAL AND 
DISEASED ORGANS OF ABIES BALSAMEA 
AFFECTED WITH AKCIDIUM ELATINUM. 
ALEXANDER P. ANDERSON 
(WITH PLATES XIV AND XV) 
. I. INTRODUCTORY. 
Hs Wirutn the last few years some attention has been given to 
. the study of the deformations and anatomical changes that take 
Place in plants when attacked by parasitic fungi. Such changes 
become more marked when the relations between host and 
_ Parasite are such that there exists a sort of mutualism between 
thetwo. In many cases the hypertrophied organs of the host 
plant lose their photosynthetic power, and thus, by assuming 
___ Parasitism, become more dependent on the normal parts of the 
Ra pe host for their existence. This is always true of the so-called 
ee wih brooms ” (Hexenbesen) on species of Abies affected 
oe cidium elatinum. Here the affected and hypertrophied 
Part of the plant becomes a morphological unit, the anatomy — 
and physiology of which departs from that of its normal hom- — 
_ The anatomy of different ‘species of Abies varies slightly _ 
les normal conditions. This is especially true of the leaves _ 
on ounger branches, which in some species have tissues and 
