Where does “rheotropism” come from?

rheotropism (English) comes from English rheo-, from Ancient Greek ῥέω, from Proto-Indo-European srew-, from Proto-Indo-European ser- — to flow; to guard; to bind, to tie together.

rheotropism (English): movement stimulated by a current of water

Definitions

movement stimulated by a current of water

Ancestry of “rheotropism”, step by step

Step	Language	Word	Meaning
1	English	rheo-	flow, current
2	Ancient Greek	ῥέω	I flow, stream, run, gush; I let flow, pour; I...
3	Proto-Indo-European	srew-	to flow, stream
4	Proto-Indo-European	ser-	to flow; to guard; to bind, to tie together

Every word from Proto-Indo-European ser- →Every word from Proto-Indo-European srew- →Every word from Ancient Greek ῥέω →