OF SAP IN PLANTS. 3 



By this means it is possible to test, by direct experiment, the 

 directions and course of the flowing saps from the root to the 

 leaves, and backwards to all the other organs, which the follow- 

 ing observations attempt to do in regard to the more important 

 families of plants. 



I. ACOTYLEDONS. 



1. Fungi. 



Clavaria rvgosa, Bull. — A number of these fungi (with unin- 

 jured radical filaments imbedded in earth) were placed with the 

 lowest part in an aqueous solution of ferrocyanide of potassium : 

 in twenty-four hours they had become thoroughly imbued with 

 it, so that a blue colour was produced when the tips were merely 

 slightly touched with chloride of iron. 



When a cross section of the upper part of the fungus was 

 made, and the surface of this tested, a blue colour was also pro- 

 duced, but of very different intensity in different parts of the 

 section. One part remained almost white, while the central 

 portion, as w^ell as a zone within the layer of rind, was strongly 

 coloured : the hymenial layer was tinged but very slightly, which 

 appears to depend partly on the great density of the cellular 

 tissue, offering more resistance to the passage of the juices, and 

 partly on the similar eflfect of the horizontal position of its cells. 

 The cells of the interior were of perfectly similar character, 

 but they seemed to be more loosely packed under the cortical 

 layer and in the central part, and the more active conduction of 

 the fluid is connected with this. The walls of the cells, and 

 also the fluid between them, were coloured blue. Longitudinal 

 sections exhibited exactly the same results. 



Scaphophorum agaricoides, Ehrb. — The little branch to which 

 the fungus was attached was dipped into the fluid, without 

 wetting the fungus itself. In twenty-four hours the fluid had 

 made its way to about the middle of the fungus ; when chlo- 

 ride of iron was dropped on the surface, a blue colour w^as 

 produced, and this arrested the further penetration of the ferro- 

 cyanide of potassium toward the border, so that the latter did 

 not exhibit any reaction even after two days. 



Although this fungus is composed of uniform elementary 

 structures, the reaction of the different layers displayed very 



1* 



