Primary and Secondary Association in Taraxacum

INTRODUCTION,Y extensive studies of the early stages of meiosis the English school B of cytology (DARLINGTON and his co-workers) has succeeded in presenting a clear and uniform picture of the process of chromosome pairing and the causes of that ))variety of mitosis)) which meiosis constitutes (DARLINGTON, 1932).The most important points of this fundamental theoretical structure are the following:During the leptotene stage the chromosome threads are undivided, they are paired at zygotene, split lengthwise at pachytene, and by ex-