In South Africa, three aloe species belonging to section Anguialoe (Aloe spicata L.f., A. castanea Schonl., and A. vryheidensis Groenewald; Fig. 1A) have dark redbrown nectar with a distinctive bitter taste to humans (S.D. Johnson and A. L. Hargreaves, personal observation). The dark color and bitter taste of the nectar in these species are due to phenolic compounds (S. D. Johnson and F. van Heerden, unpublished data).