Members of Solanum series Conicibaccata in Mexico and Central America are very similar. All are tetraploids (2n = 4x = 48). Recent authors have recognized three or four species: S. agrimonifolium, S. woodsonii, S. longiconicum (sometimes included in the next), and S. oxycarpum. We had difficulty distinguishing these species in the herbarium, and needed to resolve species boundaries for ongoing floristic studies. We studied this group in the field throughout Mexico, Guatemala, Costa Rica, and Panama, grew collections in the greenhouse, studied herbarium specimens, determined ploidy levels through flow cytometry, and generated molecular data using Random Amplified Polymorphic DNA. Molecular data distinguish S. agrimonifolium, S. longiconicum, and S. oxycarpum. Solanum woodsonii was not available for molecular analysis. All four species can be distinguished morphologically, but only by leaf character states that overlap in range, by pubescence differences that are best observed in living specimens, and by a seed spot character that is only evident on living or recently gathered specimens.