On the Anatomy of some Tubers. 
BY 
T. REED, A.R.C.S. 
Biology Department: St. Mary s Hospital Medical School. 
With Plates XLII and XLIII and four Diagrams in the Text. 
T HE investigation of the anatomical structure of tubers has been much 
neglected. Hitherto no account appears to have been published 
dealing with the anatomy of the potato, Solatium tuberosum , or with that 
of the artichoke, Helianthus tuberosus. 
Several attempts have been made to determine the causes which bring 
about tuberization in the potato. In a long series of papers N. Bernard ( 1 ) 
has attempted to show that tuberization in the potato is a result of the infec¬ 
tion of the plant by a fungus. By inoculating the cortex of the roots of 
young plants of S', tuberosum with the spores of the fungus Fusarium , he 
claims that he obtains a greater yield of tubers than he does in the case of 
plants which are not artificially inoculated with the fungus spores. He does 
not explain why infection should cause tuberization in a totally different 
part of the plant from that which is actually infected. It will be difficult to 
explain why infection of the root by the fungus should cause tuberization in 
the stems, for in no case has the fungus been traced from the root to the 
tubers. In the case of attacks of fungi on plant tissue it is usual to find the 
part actually infected becoming meristematic and forming tubercular growths 
such as we get in the cases of galling, witches’ brooms, &c. Bernard tenta¬ 
tively suggests that it may be an action a distance by the fungus, brought 
about by its giving rise to soluble products which in some mysterious way 
cause the underground stems to swell up and accumulate vast reserves of 
carbohydrates, &c. 
H. Jumelle ( 9 ) has caused some doubt to be thrown on the work of 
Bernard. Repeating some of Bernard’s experiments, Jumelle does not appear 
to confirm his results, and he says that the results, in his opinion, are not 
sufficiently clear to convince him of the conclusions drawn by Bernard. 
In Bernard’s third experiment he describes a case in which the potatoes 
were grown en pleine terre. The first lot were assured of infection by being 
[Annals of Botany, Vol. XXIV. No. XCV. July, 1910.] 
