Persicaria lanigera
Polygonaceae Fortnight: Persicaria lanigera from Delhi-GSMAY35 : 3 posts by 3 authors. Attachments (2).
Persicaria lanigera (R. Br.) Sojac
syn: Polygonum lanigerum R. Br.
Avaery distinctive species of wet places easily identified by its white lanate leaves and terminal condensed inflorescence. Could capture it only in vegetative state. 
Photographed from banks river Yamuna in Wazirabad, Delhi.
Thanks for sharing the images Sir! I've seen this plant in Dehra Dun..that too in vegetative stage. :-(
Wondering how much it differs from P. lapathifolia var. lanosa. Yet to see in field.

I have also seen its flowers, it is a robust herb..