The Influence of Fruit-bearing on the De- 
velopment of Mechanical Tissue in some 
Fruit-trees 1 . 
BY 
ADRIAN J. PIETERS, 
Assistant Botanist, U. S. Department of Agriculture. 
Historical. 
T HE attention of botanists appears to have been first 
drawn to the difference between the anatomical struc- 
ture of the flower-stalk and that of the leafy stem by the 
work of Oels in 1879 2 . Oels studied the Droseraceae, and 
found little difference between the structure of the axis of 
inflorescence and that of the leafy stem. 
In a paper published in 1886, Klein 3 states that on passing 
upward from the axis of an inflorescence into the pedicels of 
the individual flowers the following changes were observed 
(1) an increase in the amount of cortex, this increase being at 
the expense of the wood and pith, chiefly at the expense of 
1 The laboratory work for this paper was done under the direction of Prof. F. C. 
Newcombe in the botanical laboratory of the University of Michigan. The 
writer desires to thank Prof. Newcombe for his kindness and assistance, not 
only while under his immediate direction, but also while preparing the notes for 
publication. 
2 Oels, W., Bau des Stengels und der Bliithenstandaxe bei den Droseraceen. 
Inaug. Dissertation, Breslau, 1879. Ref. in Bot. Jahresbericht, 1879, 1. Abt., 43. 
3 Klein, O., Beitrage zur Anatomie der Inflorescenzen. Inaug. Dissertation, 
Berlin, 1886. Ref. in Bot. Jahresbericht, 1886, 1. Abt., 901, and Bot. Centralblatt, 
1887, 32 ; 107-110. 
[Annals of Botany, Vol. X, No. XL. December, 1896.] 
