CONTENTS. 



PAGE 



Comparison of the fruit of Opuntia fulgida ■with those of other angiosperms . . 5 



Vegetative structure of Opuntia fulgida 8 



Reproductive organs of Opuntia fulgida 9 



Origin and structure of the flower 9 



Development of the wall of the ovary with its tubercles 9 



Structure and fate of the leaves of the ovarian wall 10 



Areoles or axillary buds of the ovarian wall 11 



Number, size and distribution of the areoles 12 



Origin of the growing point of the areole and sequence of initia- 

 tion of its organs 12 



The trichomes of the areole 13 



The nectaries of the areole, their distribution and morphology. ... 14 

 Spines or thorns of the areole, their distribution, structure, and 



fate 15 



Bristles or spicules of the areole, their number, structure, and 



fate 16 



The perianth, stamens, style, and stigmas, their development and 



abscission 17 



Morphology of the ovary 20 



The fruit: Its structure, persistence, and fate, normal and abnormal. ... 25 



The fruit at the time of abscission of the perianth 25 



The mature fruit 27 



The perennating fruit : Its structure and secondary growth 29 



The seed: Its structure, persistence, and germination 32 



Proliferation of flower and fruit 35 



Proliferation from attached flower buds 35 



Proliferation of persistent attached fruits 37 



Proliferation of fallen fruits 38 



Causes and significance of perennation and of the diverse types of 



proliferation 41 



Proliferation of flower or fruit in allied species 47 



Proliferation of joints and fruits in relation to the sterility of fruits 51 



Summary and conclusions 53 



Literature cited 56 



Explanation of plates 57 



