From the pictures you posted, the plant looks like a variety of Crassula, which is commonly known as a jade plant or tree. They are succulents, specifically leaf succulents, whereby water is stored in the leaves. The 'white residue' that was previously refferred to actually aids in the exchange of gasses between the leaves and air; this residue is harmless and should not be wiped off (everytime I see one , for some reason I am compelled to wipe off a leaf-I don't know why :shrugs: ).
Jade plants are, however, used frequently in vivs and are perfectly safe to put with snakes. They require watering only every few weeks, yet they do require medium to intense light, like other succulents and cacti that they are related/similar to.
Although, you should remember to always rinse the plant off well and a few times before placing it with your snake, do to the fact that it may have fertilizer and/or pesticides present on it or in the soil---which both are harmful to snakes. If you have had the plant for a long time, and have never fertilized it (ie. miracle grow) or applied pesticide, then it is already safe. Hope this helps.