I got the difference between Galinsoga quadriradiata & Galinsoga parviflora, which could be easily checked: 
Galinsoga parviflora:  upper part of the stem not hairy or with short and sparse simple hairs
Galinsoga quadriradiata: upper part of the stem with glandular hairs and dense simple hairs
http://www.kuleuven-kulak.be/bioweb/?lang=fr&detail=164

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Pl. go through Galinsoga page (‎‎‎Asteraceae (Compositae)) with images of species in efloraofindia (done by …).

If you find any mis-identification, pl. let us know.
If anybody can send images of other species of this genera (for incorporation in the website), it will be really nice. Also, if anybody is interested to take up the activity of inserting images on efloraofindia pages from efloraofindia posts, pl. let us know.