From left to right: P. pensylvanica, P. hydropiperoides, P. longiseta, P. punctata, P. glabra, P. lapathifolia.
Second photo, the one on the bottom is H. hydropiperoides (P. pensylvanica is on top).
Ambiente ripariale, 780 m.
Polygonum ilanense Y.C.Liu & C.H.Ou 1976 https://powo.science.kew.org/taxon/urn:lsid:ipni.org:names:695895-1
NOT Persicaria foliosa (H.Lindb.) Kitag.
Reference observation:
https://www.inaturalist.org/observations/232920381
https://www.inaturalist.org/observations/226387444
https://www.inaturalist.org/observations/229773710
https://www.inaturalist.org/observations/91948643
Polygonum ilanense Y.C.Liu & C.H.Ou 1976 https://powo.science.kew.org/taxon/urn:lsid:ipni.org:names:695895-1
NOT Persicaria foliosa (H.Lindb.) Kitag.
Reference observation:
https://www.inaturalist.org/observations/232920381
https://www.inaturalist.org/observations/226387444
https://www.inaturalist.org/observations/229773710
https://www.inaturalist.org/observations/91948643
ID by CK Yang