To cite an IBIS-Flora whole as concept:
Deomurari, A.; Jani, M.; Matieda, K.; & KaPatel, J.; IBIS-Flora, retrived from http://flora.biota.in/. Accessed 15 Jan 2014.
To cite an IBIS-Flora Page:
For a single species we recommend you to cite species profile page. As with most web pages, you can find a list of authors and editors in the left slide top:
Jani, M.; Deomurari, A.; Matieda, K.; & KaPatel, J.; " Acorus calamus L." IBIS-Flora, available from http://flora.biota.in/pages/460427. Accessed 15 Jan 2014.