The cascade stands about 5 in from highest leaf tip to base of pot. I couldn't find the owner so will have to give a best guess. I'd say a mulberry. The accompanying planting is about 2 in high (including the pot) and the same across, it could be a pennywort or a very, very, very small geranium. To give an idea of scale, the rectangular wooden display stand is about 8 inches in length.
What is really notable is that the whole composition is an accent to a suiseki. The stone is lovely in its own right, but this was the first time I'd seen a mame + accent together used as an accent. The suiseki itself is rather large, so I wouldn't be able to fit the entire display in a single photo. Will try and get through the crowds tomorrow to take a photo of the stone.