Zain...the best place, in my opinion, to find the accepted name of a species is located here:
Royal Botanic Gardens, Kew: World Checklist Series
You type in the the species and genus and you get the info. It is a good research tool. You can also bring up a full list of a genus, accepted and non accepted names, by typing in just the genera name. The database here is live and updated daily but sometimes it can take up to a year, after a paper is published, for it to be added to the database.
Hope you find this helpful