Surajit: good you got them....
this is peeta bhringaraj in Sanskrit
called simply bhringaraj in bengali
if you ask the local green leaf/herb vendor to get you bhringaraj in WB this what you'll get
Hort plants these in big long rows all over every year .
elliot park on chowringhee used to do so too!
In most of rest of india, herb vendor/supplier would get you ... eclipta alba, bhringaraj....