KYPARISSOS (or Cyparissus) was a handsome youth from the island of Keos (Ceos) loved by the god Apollon. He died of grief after accidentally killing his beloved pet stag and was turned into a cypress tree.
TELEPHOS (Servius on Virgil's Aeneid 3.64)
CYPARISSUS (Kuparissos), a youth of Cea, a son of Telephus, was beloved by Apollo and Zephyrus or Silvanus. When he had inadvertently killed his favourite stag, he was seized with immoderate grief, and metamorphosed into a cypress. (Ov. Met. x. 120, &c.; Serv. ad Aen. iii. 64, 680, Eclog. x. 26, Georg. i. 20.)
Source: Dictionary of Greek and Roman Biography and Mythology.
Ovid, Metamorphoses 10. 106 ff (trans. Melville) (Roman epic C1st B.C. to C1st A.D.) :
"In all the throng the cone-shaped cypress stood; a tree now, it was changed from a dear youth loved by the god who strings the lyre and bow [i.e. Apollon]. For there was at one time, a mighty stag held sacred by those nymphs who haunt the fields Carthaean [i.e. on the island of Keos]. His great antlers spread so wide, they gave an ample shade to his own head. Those antlers shone with gold: from his smooth throat a necklace, studded with a wealth of gems, hung down to his strong shoulders--beautiful. A silver boss, fastened with little thongs, played on his forehead, worn there from his birth; and pendants from both ears, of gleaming pearls, adorned his hollow temples. Free of fear, and now no longer shy, frequenting homes of men he knew, he offered his soft neck even to strangers for their petting hands. But more than by all others, he was loved by you, O Cyparissus, fairest youth of all the lads of Cea. It was you who led the pet stag to fresh pasturage, and to the waters of the clearest spring. Sometimes you wove bright garlands for his horns, and sometimes, like a horseman on his back, now here now there, you guided his soft mouth with purple reins.
It was upon a summer day, at high noon when the [summertime constellation] Crab, of spreading claws, loving the sea-shore, almost burnt beneath the sun's hot burning rays; and the pet stag was then reclining on the grassy earth and, wearied of all action, found relief under the cool shade of the forest trees; that as he lay there Cyparissus pierced him with a javelin: and although it was quite accidental, when the shocked youth saw his loved stag dying from the cruel wound he could not bear it, and resolved on death. What did not Phoebus say to comfort him? He cautioned him to hold his grief in check, consistent with the cause. But still the lad lamented, and with groans implored the Gods that he might mourn forever. His life force exhausted by long weeping, now his limbs began to take a green tint, and his hair, which overhung his snow-white brow, turned up into a bristling crest; and he became a stiff tree with a slender top and pointed up to the starry heavens. And the God, groaning with sorrow, said; ‘You shall be mourned sincerely by me, surely as you mourn for others, and forever you shall stand in grief, where others grieve.’”
Nonnus, Dionysiaca 11. 362 ff (trans. Rouse) (Greek epic C5th A.D.) :
"A young Lakonian [i.e. Hyakinthos] shook Zephyros (the West Wind); but he died, and the amorous Wind found young Kyparissos (Cyparissus) a consolation for Amyklaian Hyakinthos (Amyclaean Hyacinthus)."
- Ovid, Metamorphoses - Latin Epic C1st B.C. - C1st A.D.
- Nonnos, Dionysiaca - Greek Epic C5th A.D.
Other references not currently quoted here : Servius on Virgil's Aeneid, Eclogues & Georgics