﻿1916J GATES- XEROFOTIC MOVEMENTS 401 



and Voandzeia subterranea, all belonging to the Leguminosae, 

 the following were selected for study on account of their suitability 

 and convenience: Gliricidia scpium of the subfamily Papilionatae, 

 and Leucaena glauca and Mimosa pudica of the subfamily Mimo- 



Amount of movement.— As the normal day position of the 

 leaflets of legumes is a plane at approximately right angles to 

 the light, the amount of movement can easily be expressed as 



der stimulation of direct sunlight; Los Baiios, P.I., July 29, 1914. 



the amount of divergence from the horizontal. Whether the night 

 position of the leaflets is erect or drooping, the xerofotic position 

 is between 45 0 and 70 0 above the horizontal (figs. 1 and 2). 

 When the night position of the leaflet is above the horizontal, 

 as is the case with many members of the Mimosatae, the xerofotic 

 position differs in not exceeding 70 0 above the horizontal and in 

 the absence of a forward movement often a part of the photeolic 

 response. The horizontal position is assumed always between the 

 xerofotic and the night positions. 



Inequality and irregularity of the movement. — Generally 

 speaking, the upward bend is equal in each leaflet of a pair and 

 likewise in a series of pairs. The exceptions note. I in nature and 



