Secondary sex characters inAsparagus officinalisL.

Abstract

does not appear. First page follows. Introduction Common asparagus is normally dioecious. Casual observations in the field reveal no striking differences between the two sexes in their vegetative characters. Careful studies, however, show that there are significant quantitative differences between staminate and pistillate individuals. Secondary sex characters in plants are far less striking than they are in animals. It is probably for this reason that they have received so little attention. Cowles(1) calls attention to the fact that “immediately after flowering it often is possible to distinguish at some distance pistillate from staminate mulberry trees by their much smaller leaves, as though the constructive material in the former were utilized chiefly in fruit development, and in the latter, in leaf development.” Later in the season, the leaves are equally large on both pistillate and staminate individuals. Guinier(3) states that dioecism in the case of Pinus montana and P. sylvestris is accompanied by a certain vegetative dimorphism. In purely staminate individuals, the branches terminating in inflorescences have the cones distributed over the greater part of the new shoots, a relatively small area being left at the apex for the short, leaf-bearing twigs. After these male cones have fallen, there is left a long bare section at the base of each new shoot, the leaves forming a tuft at the tip of the shoot.