I consider some begonias succulents!
Just like some euphorbia are succulents, yet others are drought sensitive hardy ground cover, or tropical shrubs...
Some genus fit the mould ! Succulent or not!
Others sneak outta the mould here and there, a few blow that mould away!
I believe by definition a succulent plant will have water storage in its anatomy, be it stem or leaf, or even root!
Consider the ever popular ( super popular here on ATP) daylily!
Few would consider it succulent, but dig one up, look at those thick juicy SUCCULENT roots!
If you doubt their succulent nature, dig one, put it in a clay pot and treat it like a succulent, as long as don't use gritty mix, or live in hot hot fenix, you can I. Fact grow them side by side with other c&s, as a matter of fact, you may find yourself watering bonified succulents more often, crown of thorns, aeonium, some kalanchoe, some crassula, come to mind, but there's many others!
In my book, if I can take a coin sized piece of the plant, single layer , not folded over, and crush it between my finger and thumb, and a drop of water emerges from it, then it's a semi succulent, bare minimum! Maybe even a true succulent!
Begonias defiantly fall into this category for me!
