18 



NEW YORK STATE MUSEUM 



a petal (figure 44G). They are usually but not always brightly colored. 

 Subtending or beneath the corolla is the calyx, which is usually, but not 

 always, green, and is likewise in many plants divided into a number of 

 distinct parts or sepals. When an incomplete flower has but one set of 

 floral envelopes, it is usually the petals (or corolla) which are lacking, and 

 in such cases the calyx may be brightly colored and function as a corolla 

 (a petaliferous calyx). 



The essential organs: 



The number and arrangement of stamens varies in different kinds of 

 plants, but nearly always a stamen consists of a filament or stalk (figure 

 44E), which bears at its apex the anther (figure 440), or pollen -bearing 

 sac. The shape of the anther, and the manner by which it dehisces, or 

 opens to emit the pollen, likewise varies in different groups of plants. 



The pistil (figure 44A-C), or seed-bearing organ, consists of an ovary 

 (figure 44A), stigma (figure 44C) and style (figure 446). The ovary is at 



the base of the pistil and contains the 

 ovules or eggs, which after fertilization 

 ripen into seeds. The ovary usually con- 

 tains several or many ovules, but may 

 contain as few as a single ovule. The 

 stigma is that part of the pistil which 

 acts as a receptive organ for pollen in the 

 process of pollination. Its surface is 

 usually moist and minutely granular and 

 its position and shape are dependent upon 

 the mode of pollination (insects or wind) 

 made use of by the particular plant. The style connects the stigma and 

 ovary. It may be long or short, slender or stout, or sometimes entirely 

 lacking when the stigma is situated directly upon the ovary. 



The ovary itself may contain one or several chambers or cells (figures 

 45-47), and very frequently the number of chambers in the ovary and the 



45 



46 



47 



