The Time of Origin of the Flowering Plants Determined by Using Amino Acid Sequence Data of Cytochrome C

S ummary Cytochrome c sequences from nineteen plants have been used, in conjunction with those of animal and fungal origin already published, to calculate the times of origin of the animal, fungal and plant kingdoms and also of some higher plant groups. The results show that the Angio‐sperms originated at least several geological periods before the Cretaceous, which is the earliest period in the geological record in which authentic angiosperm fossils have been found.