512 Pieters. — Influence of Fruit-bearing on 
the latter ; if) in the flower-stalk there was often no pith, 
because the bundles were crowded together in the centre. 
This became even more marked in the fruit-stalk, in which 
the necessity of an abundant supply of building-material and 
of mechanical support for the fruit resulted in the bundles 
taking a more central position. 
Nanke 1 in 1886 worked on Pirns Mains and on P. com - 
munis , as well as on several other plants. He found that the 
cells in the fruit-stalk were smaller than those in the leafy 
shoot. This difference was most conspicuous in the wood- 
cells. 
In 1887 Dennert 2 published the results of an examination 
of ] 80 species. He found an increasing delicacy of structure 
in passing from the leaf-shoot into the axis of inflorescence 
and thence into the pedicels. This change consisted in 
a weaker development of wood and pith from below upward. 
Dennert found that at the time of ripening of the fruit there 
was an increase in the development of mechanical tissue. 
This was manifested by an increase in the extent of xylem 
and in the thickness of the walls of the wood-fibres. The 
medullary rays of the stem were usually lacking in the fruit- 
stalk. An increase of hard bast did not occur where there 
was an abundance of wood, and vice versa. 
In the same year Reiche 3 presented some work on addi- 
tional species. His work confirms the results obtained by 
preceding authors. 
In all this work the flower-stalk or the fruit-stalk was 
compared with the leafy stem. It was a study in the 
adaptation of organs to the demands made upon them, as 
1 Nanke, W., Vergleichend-anatomische Untersuchungen liber den Bau von 
Bliithen und vegetativen Axen dicotyler Holzpflanzen. Inaug. Dissertation, 
Konigsberg, 1886. Ref. in Bot. Jahresbericht, 1886, 1. Abt., 902, and Bot. 
Centralblatt, 1 886, 32, 33; 145-147. 
2 Dennert, E., Metamorphose der Bliithenstandaxen : Bot. Hefte, Forschungen 
aus dem Bot. Garten zu Marburg, Heft 2, 128-217, 1887. Ref. in Bot. Jahresbericht, 
1887, 2. Abt., 647. 
3 Reiche, K., Beitrage zur Anatomie der Inflorescenzen ; Berichte der Deutschen 
Bot. Gesells., 1887, V, 310-318. 
