Mellyrn don't sing, do they?

[HerenIstarion]

Well, since question of singing gold 'things' seems settled (my compliments, Guinevere ), let us turn to mellyrn and their origin.

There were two waves of 'expansion' of mallorns to Middle-Earth, and both came from Valinor:

Second Age, through Númenor and Galadriel to Lothlórien

First Age, through exiled Noldor.

This latter has indirect evidence for a support:

Silm77, Of Eldamar and the Princes of the Eldalië

For all living things that are or have been in the Kingdom of Arda, save only the fell and evil creatures of Melkor, lived then in the land of Aman; and there also were many other creatures that have not been seen upon Middle-earth, and perhaps never now shall be, since the fashion of the world was changed

and

UT, Christopher Tolkien's notes to 'Of the Coming of Tuor To Gondolin'

A description of Gondolin was to follow, of the stairs up to its high platform, and its great gate; of the mounds (this word is uncertain) of mallorns, birches, and evergreen trees; of the Place of the Fountain, the King's tower on a pillared arcade, the King's house, and the banner of Fingolfin

The theory hence:

Since 'living things' include trees, and since only mention of mellyrn in Beleriand is in Gondolin, it is to be assumed that Noldor brought them originally. So, 'First Wave' - Valinor - Noldor - Gondolin. M-E mellyrn become extint with the drowning of Beleriand, and the 'Second Wave' comes again from Valinor though Tol Eressea and than Númenor

It would have been interesting to speculate about seeds that may have been saved by Tuor and been brought in time to Númenor, whence they would have been re-introduced to Middle-Earth through Tar-Aldarion and Galadriel, but quote provided by Guinevere (Trees brought by Elves of Tol Erëssea to Eldalondë) above forbids speculations of the kind