Excised internodal segments of flowering specimens ofVerbascum thapsus, with and without vascular tissues, were grown on a nutrient medium which lacked added growth regulators such as auxin and cytokinin. Stem segments which contained vascular tissues formed numerous buds in superficial layers of newly formed tissue within two weeks after transfer of the explants to the medium. Tangential cell divisions in the cambium and phloem are thought to be primarily responsible for the newly formed tissue. A regenerated bud displays dendritic trichomes on its first leaf primordium, whereas the earliest that such trichomes appear on intact seedlings is on the second foliage leaf primordium. Pith explants without vascular tissues become brown in a matter of two to three weeks with no visible sign of growth. Endogenous growth regulators supplied by vascular tissues are believed to be major factors in bud formation in excised internodal segments of this species.