@PA und judex:
using trivial names has two problems:
1- PA has already mentioned - not all animals, etc., have a trivial name in both languages,
and, more serious, imo,
2- many animals, and plants have a lot more trivial names than one might think, including international differences, regional names, and so on, so that the only definitive way of identifying them is to use the scientific name, and perhaps link some sites in both languages to them.
It is probably an impossible task to list all species of plant, insect and so on, in LEO, and more sensible, imo, to list families, or groups, with exception of those plants that are so everyday, or singular, that no confusion with others is possible.
But that is up to LEO, and not an enviable task at the best of times.