In article ,
Iris Cohen wrote:
I know the species epithet has to agree with the genus name, and that tree
names are generally feminine. The word arbor itself is feminine. (You'll never
convince me that a ponderosa pine is feminine.)
Now, would somebody please explain Punica granatum and Heptapleurum arboricola.

I think it's because precedence takes precedence even over poor Latin.
I.e. whatever name was given in the first "legal" description stands; even
if there's a mistake. Another example was Sedum rosea - corrected when it
became Rhodiola rosea recently. Linneus himself made a similar mistake
when naming the Cat's Ears as Hypochaeris rather than Hypochoeris, since the
greek word for pig he based it on is choeros. He later corrected himself,
but the rules say that since he used an a the first time this spelling must
stand. (You will still find both spellings in use in modern books - about
50:50. This makes me sound very erudite, but in fact this was discussed in
these very columns a few years ago and I am only repeating what came out
then!)

Howard Clase