Noteworthy anatomical and physiological researches. 
Root-tubercles on Ailanthus.! 
The tumors upon roots of phanerogams have been studied 
extensively during the last decade. To the list of plants 
known to possess root-tubercles we can now add Ailanthus. 
Upon the roots of a tree of A. glandulosa cultivated in the 
botanical garden of Erlangen, Ernst Andrez discovered nu- 
merous tubercles. These tubercles were outgrowths of very 
irregular shapes, varying from 5 to 40™™ in diameter and were 
most frequently grown together in clumps of three or more. 
The surface of the tubercles was scabrous, almost warty. 
One root showed a peculiar development of not only a num- 
ber of these tubercles, but also an innumerable mass of 
lateral roots, all of which were of the same thickness and ap- 
proximately of the same age. These roots were tangled up 
and more or less grown together, reminding one of some 
coarse fungus mycelium. 
Two questions arise in regard to the origin of the tubercles: 
are they due to parasitic organisms, or merely to mechanical 
influences, disturbances in the functions of nutrition, etc.? 
The author bases his teply to these questions upon the results 
of a very careful anatomical study of the roots and the 
tubercles. 
He describes minutely the structure of the various forms of 
tubercles. An old tubercle shows distinctly the original 
that longitudinal and transverse sections are almost alike. This 
is seemingly due to the fact that the growing-points of new 
roots and root-shoots developin almost any direction, and so the 
tubercle obtains its roundish shape. Most of these rudiment- 
ary roots and shoots do not develop any further. Sometimes, 
however, they grow so as to form lateral tubercles, but most 
often they constitute the warty mass which characterizes the 
surface of the tubercles. 
Some fungi were observed by an examination of the struct- 
ure of the tubercles. They were supposed to belong to the 
‘Ernst Andree: Ueber abnorme Wurzelanschwellungen bei Ai/anthus gland- 
ulosa. Inaug. diss, Erlangen 1894. 
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