Unlikely that will ever be clarified! They are very similar and often hybridise. The leaf-shape can help to distinguish the species. Flower colour is extremely variable...all shades of pink and purple! Dolichantha tends to have darker flowers.

Chinese Salvias are a nightmare to be positively identified....eg...so much confusion re S. digitaloides and S. campanulata.....not to mention S. omeiana and S. smithii!!!

Know I have been completely unhelpful,

Robin.

Quite amazing. Is there no official (Chinese) key to these Salvias? Somebody must ever have invented these names and I imagine that there are official (scientific) descriptions. Or am I wrong?

There is an official Flora of China, but that only works with type specimens of the plants. There are not enough specimens collected for many species to map out variability, and only wild-collected seed should be trusted for authenticity.

They cross a great deal in gardens, and also behave differently under various microclimates. Flower size is especially variable, and Chinese sages generally do poorly in subtropical climates. They do especially well on the West Coast and the Front Range (Colorado in particular), then in the colder parts of the Midwest and Northeast.