76 TRANSACTIONS OF THE [Sess. lxxx 



The Influence of Different Media on the Histology 

 OF Roots. By Sophie J. Wilkie, B.Sc, Carnegie 

 Scholar, St. Andrews University. (Plate I.) 



(Read 14th October 191.').) 



The following is a short note on the differences found in 

 the anatomical structure of the roots of Monstera deliciosa, 

 Liebni., when grown 



( 1 ) In air. 



(2) In soil. 



(3) In water. 



(4) In wet gravel. 



(5) In damp soil. 



Constantin in a paper published in the Annales des 

 Sciences Naturelles, ser. 7, tome i, 1885, pp. 135 to 178, 

 gives an account of the differences found in the structure of 

 roots when grown in air, soil, and water. 



His general conclusions are : — 



(1) That aerial roots are characterised by the strong 

 development of the central cylinder and of the vascular and 

 stereom tissues. 



(2) That soil roots show a reduction in the amount of 

 pith ; sclerenchyma and lignified vessels are of minor 

 importance, and there is a very broad outer cortex. 



(3) Water roots are very similar to soil roots, but they 

 differ in respect that tliey possess large intercellular spaces, 

 and the vascular system is weaker. 



In Constantin's opinion the most important point which 

 his research brings to light is that lignin is developed with 

 difhculty in soil and water roots. 



Haberlandt (Wollny's Forsch. — Inlluence of moistui'e 

 on the development of stereom, I, pp. v. sqq.) showed that 

 the development of the mechanical tissue is affected by the 

 humidity of the soil. He found that an increase in the 

 water content of tlie soil had a favourable effect on the 

 development of the mechanical tissue of (Jannabis sativa, 

 Linn. 



The material used for the following work on Monstera 

 deliciosa was fixed in con-osive sublimate, and after wash- 



