How to get the closest related, sequenced and annotated species?

Question

[FJK]

Hi,

I'd like to obtain the closest related species for a given species. In addition, I'd like to specify whether I'm interested only in sequenced and annotated species. At best I would like to specify the number of returned results/species.

Is there a database or search engine for that kind of questions? My main focus are plants, but the question is not restricted to plants.

best regards, Jens