The African violet, one of the world’s most popular houseplants, has a new botanical name. (To further understand why botanical names change, read the article Why Do Plant Names Change.)
This plant has been known as Saintpaulia ionantha, in honor of its discoverer, Baron Walter von Saint Paul-Illaire, since 1892. However, recent genetic studies now place this gesneriad in a different genus, Streptocarpus, more specifically in the subgenus Streptocarpella. Theoretically, you should therefore call your African violet Streptocarpus subgenus Streptocarpella sect. Saintpaulia. However, Streptocarpus ionanthus would also be perfectly legitimate … and much less cumbersome!
That means the species from which most African violet cultivars are derived, Saintpaulia ionantha, officially becomes Streptocarpus sect. Saintpaulia ionanthus (note that ionantha becomes ionanthus to match the gender of Streptocarpus), or much more simply, just Streptocarpus ionanthus. That’s now the name used on Wikipedia.
The typical African violet you grow in your home, typically a hybrid, would now be called legitimately called Streptocarpus ionanthus followed by its cultivar name in simple parentheses. For example, Streptocarpus ‘Blue Boy’.
No doubt we’ll continue to use names like Saintpaulia ‘Blue Boy’ for a long time and even the author of the change, Dr. Jeffrey Smith, botanist at Ball State University, admits that this use is not necessarily illegitimate, as long as it is clearly understood that the proper botanical name is Streptocarpus sect. Saintpaulia.
The two leading authorities on gesneriad nomenclature, The African Violet Society of America and The Gesneriad Society, both propose to continue to use the name Saintpaulia in non-scientific texts, but without italics. (I assume they will use the full name [Streptocarpus subgenus Streptocarpella sect. Saintpaulia] in situations where that is required.) Following their lead, you could write Saintpaulia ‘Blue Boy’ (note the absence of italics) rather than Saintpaulia ‘Blue Boy’ as in the past. That’s a good compromise and an easy one to apply! And it means I won’t have to change the labels on all my African violets!