The Commentaries of Servius
Another Roman tradition makes the lover out to be the woodland god Silvanus. An invocation by Virgil of "Silvanus who bears the slender cypress uprooted" was explained in the commentary of Servius as alluding to a love affair. In his brief account, Servius differs from Ovid mainly in substituting Silvanus for Apollo, but also changes the gender of the deer and makes the god responsible for its death:
Silvanus loved a boy (puer) named Cyparissus who had a tame deer. When Silvanus unintentionally killed her, the boy was consumed by sorrow. The lover-god turned him into the tree that has his name, which he is said to carry as a consolation.
It is unclear whether Servius is inventing an aition, a story to explain why Silvanus was depicted holding an evergreen bough, or recording an otherwise unknown version. Elsewhere, Servius mentions a version in which the lover of Cyparissus was Zephyrus, the West Wind. The cypress, he notes, was associated with the underworld, either because they don't grow back when pruned too severely, or because in Attica households in mourning are garlanded with cypress.
Read more about this topic: Cyparissus