Root initiation in the adult axes of a few dicotyledonous species

Abstract

Six additional cases of naturally occurring shoot-borne adventive roots on adult axes of herbaceous dicotyledons have been described in this paper. These support the view of Priestley and Swingle that the site of initiation of a lateral root in adult hypocotyls and intemodes moves inwards from the pericycle to the flanks of the vascular cambium close to the newly differentiated xylem and phloem. The radial growth of the hypocotyl of Cucurbita maxima is maintained by the independent growth of the vascular bundles, the interfascicular cambium helping the primary rays in keeping pace with the growth in thickness of the former.