Learn how to say Polygonum correctly in English with this tutorial pronunciation video.
Oxford dictionary definition of the word polygonum:
a plant of a genus that includes knotgrass and knotweed, some of which are weeds and some are garden ornamentals.
Genus Polygonum, family Polygonaceae
modern Latin, from Greek polu- ‘many’ + gonu ‘knee, joint’ (because of the swollen joints sheathed by stipules)