There has been a lot of discussion about snail vine versus corkscrew vine and the names. I looked in the A-Z Encyclopedia and Hortus Third. Vigna caracalla is listed as a synonym for phaseolus caracalla as is phaseolus grandiflora. This plant is give the common names of corkscrew or snail vine in both books. Snail Vine, i.e. the purple one we call snail vine, is no where to be found in any of the books I have and when found on the internet it's listed as both phaseolus caracalla, phaseolus grandiflora and vigna caracalla.
I've been reading about both vigna and phaseolus. They are either bush type plants like bush beans and peas, or vining plants. Snail vine isn't really a climbing plant but prefers to grow along the ground(at least the ones I've had seem to prefer to run along the ground, maybe I have weird plants.) Ya know what it reminds me of? Centrosema...the butterfly pea of the southeastern US. I don't think Snail Vine is either a vigna or a phaseolus. What does everyone else think? Why isn't it in Hortus, or am I looking in the wrong place? It's been grown for years as an ornamental vine. Who do you ask when you have a question on what a plants real name is? Just something I was wondering about, lol. I guess I have too much time on my hands.