Carissa is a genus of shrubs or small trees native to tropical and subtropical regions of Africa, Australia and Asia. Until recently about 100 species were listed, but most of them have been relegated to the status of synonyms or assigned to other genera, such as "Acokanthera".
Can we infer the following?
Some Carissa species have been de-listed.

Select from the following.
I. Yes
II. It's impossible to say
III. No
The answer is: