88 ALTERATION OF POSITION. E 
In Tradescantia virginica 1 have met with opposite 
connate leaves; the altered position, however, being 
due to the union of two stems. 
Twisting of the stem is a frequent cause of the dis- 
placement of leaves (see spiral torsion), as also hyper- 

Fie. 40.—Large-coloured leaf oceupying the position of the inflores- 
cence in Gesnera, after Morren. 
