Epitypification of Heliotropium arborescens L. (Heliotropiaceae)

The plate designated as lectotype of the name Heliotropium arborescens L. (1759) does not permit a precise application of the name. The herbarium material associated with that illustration was examined in order to clarify the identity of the type material and an epitype was selected. The epitype corresponds in morphology to the taxon called Heliotropium urbanianum K. Krause (1906) in the recent literature, which is here lectotypified and synonymized with H. arborescens. The name Heliotropium arborescens has been misapplied to a predominantly Peruvian species, which should now be correctly called Heliotropium corymbosum Ruiz & Pav. (1799). The epitypification here proposed will ensure nomenclatural stability for most material from cultivation, where the name Heliotropium arborescens is widely used.