At the suggestion of Professor Dr. Schröter, I engaged in morphological-ecological studies on Himantoglossum hircinum (L.) Sprengel, that beautiful orchid which has several of its rare locations in northern Switzerland near my place of residence. Later, in the plant physiology laboratory of the Swiss Federal Institute of Technology, I conducted anatomical investigations under the guidance of Professor Dr. Jaccard. The topic was approached from two perspectives: 1) The formal development of the flower parts with special consideration of ecologically important organs. 2) The cytological development of the generative organs: the development of pollen and ovules, fertilization, and the development of the embryo. This book is a reprint of the historical original edition from 1914.