Posted: 17/10/2016 at 14:34
Larkspur is just a common name, not something to accurately ID a plant. If you want to sort out plants in your mind forget all those common names.
The annuals we know as Larkspur are Consolida, (C. regalis, C. ajacis and others). Before a name change these were called Delphinium consolida, D. regalis etc. so closely related
There are annual delphiniums, Delphinium staphysagria is a good one.
There are many more species in the Delphinium genus than we ever see.