It's just a regular BST. And, every implementation I see of a range tree/range searching, for example, doesn't put the points in the leaves like in the first image.
So, why do depictions of range trees show all the points in the leaves when that would double the amount of space required? Is it just for visualization purposes, or does it represent the output? Is a range tree just a BST with a range query? This may seem nitpicky, but it really confuses me. Graphic source: graphics.stanford.edu/courses/cs428-03-spring/03Talks/Range.pdf It isn't unique to this specific example. It's seen here: cs.uu.nl/docs/vakken/ga/slides5b.pdf and here:cs.umd.edu/~meesh/cmsc420/ContentBook/FormalNotes/MountNotes/…, even though they seem to just use regular BSTs and don't seem to put the leaves in the nodes
EDIT: It's probably just for visual purposes: http://www.bowdoin.edu/~ltoma/teaching/cs3250-CompGeom/spring16/Lectures/cg-rangetrees.pdf