Not an expert in botanical nomenclature, perhaps I'm even wrong, but I always thought that the second part of a scientific name is not the species — it's the specific epithet.
"Thus
Hedera helix (common ivy, English ivy) is the name of the species;
Hedera is the name of the genus; but
helix is the specific epithet, not the specific name."
from
https://en.wikipedia.org/wiki/...)
