The investigation of which the results are embodied in this paper was undertaken in an. attempt to gain an insight into the problems of the propagation of Clematis by means of stem cuttings. In order to be able to interpret the phenomena of regeneration induced by isolating portions of a plant, it is essential to investigate the normal anatomy in some detail. In any severed portion of a plant the first signs of abnormal cell activity in the tissues depart only slightly from the normal, and unless they can be detected and identified at their initiation it is impossible to define exactly the time and place of origin of the new growth. Accordingly the first part of the paper will deal with the normal stem -anatomy of the genus. The second part, with the changes in the anatomy resulting from vegetative propagation, and the third part with some experiments in propagation.