156 ELEMENTARY STUDIES IN BOTANY 



so that they appear to grow from the tube of the corolla 

 (Fig. 102). In the orchids, the stamen and carpel sets grow 

 together so completely that they form a very unusual looking 

 structure in the midst of the flower. The most important 

 conditions of this kind, however, appear under the following 

 definitions : 



When the sepals, petals, and stamens all arise from under- 

 neath the pistil or pistils, so that one looks within the flower 

 for the ovary (Figs. 101, 123, and 124, A), the flower is said 

 to be hypogynous (" under the pistil ") When the three 



FIG. 124. A, hypogynous flower (Potentittd) ; B, perigynous flower (apple). After 

 ENGLER and PRANTL. 



outer sets grow together and form a cup-like structure about 

 the pistil or pistils, and from the rim of this cup the sepals, 

 petals, and stamens seem to arise, as in roses and apples 

 (Fig. 124, B), the flower is said to be perigynous (" around 

 the pistil ") When all four sets grow together in such a 

 way that the sepals, petals, and stamens seem to arise from 

 the top of the ovary, so that one looks beneath the flower for 

 the ovary, as in amaryllis (Fig. 125) and iris (Fig. 127), the 

 flower is said to be epigynous ("-upon the pistil "). Hypogy- 

 nous flowers represent the most primitive condition of the 

 flower, while epigynous flowers are characteristic of all the 

 higher families of Angiosperms. 



97. Irregularity. In some flowers the members of a set 



