We here describe and illustrate the new species Solanum humboldtianum Granados-Tochoy & S. Knapp and evaluate its conservation status. The species can be categorized as endangered (EN) and is threatened by urban and agricultural expansion and deforestation and is the first Colombian species of Solanum to receive this status. Solanum humboldtianum was first collected by the great naturalists Alexander von Humboldt and Aimée Bonpland in the early part of the 19^th century, but the specimens have lain unrecognised in herbaria for over 200 years. We document phenology, distribution and other ecological data for the species, and discuss the importance of the unification of herbarium work and in-depth field study of rare taxa such as this. We also discuss the relevance of older collections to the study of biodiversity and conservation today.