Plumbago auriculata is also widely known as Plumbago capensis, a name used so often that it is even reflected in one of this species’ common names: Cape plumbago. Other common names include Cape leadwort and blue plumbago.
The confusion over the scientific name is explained by Alice Aubrey of Africa’s Witwatersrand National Botanical Garden in her account of Plumbago auriculata. In brief, Plumbago auriculata was named in 1786 by Lamarck from cultivated plants in the East Indies. Eight years later, Thunberg assigned the name Plumbago capensis from specimens collected from its native home in South Africa–it was this latter name that caught on and became commonly used. However, since Plumbago auriculata is the earlier published name, the botanical rules of nomenclature suggest giving credit where it’s due, hence Plumbago auriculata should be used. I think the difference between this scenario and the story behind Thujopsis / Dolophyllum is the era in which the “clerical” error was discovered. In recent years, conserving long-standing names occurs fairly often when a name change would generally be required for a technical reason.
The botanical garden in Colombia where this picture was taken, the Jardín Botánico José Celestino Mutis, is named in honour of a prominent Spanish botanist (2018 edit – it seems like Jardín Botánico de Bogotá is now used more frequently). Read more about José Mutis via the Encyclopedia Brittanica Online. “His Flora de Bogotá o de Nueva Granada, containing more than 6,000 illustrations, was so massive that the Spanish government could not afford to print it.”
Conservation resource link: Julie, writer of the Human Flower Project weblog, has an entry on Penstemon grahamii. It has long been argued that Graham’s beardstongue should receive some legal protection due to its rarity (less than 10 000 individuals exist). The need for protection has become yet more critical with recent proposals to explore and extract oil from the oil shale substrate on which Penstemon grahamii grows. If you are a United States citizen, you can help if you so choose–public comments are invited.