152 BOTANICAL GAZETTE [FEBRUARY 
various sun and shade plants, or of the same plants under sun and shade 
conditions. It should also permit of the determination of the photosyn- 
thetic constants of many ecologically important plants, as a part of their 
physiological life-histories, without a knowledge of which their real relations 
to their physical environment and to other competing plants cannot be 
understood.—W. F. Ganonc, Northampton, Mass. 
