Edward Thomas being who he was, it is not surprising that, in a poem of his about autumn, melancholy makes an appearance. At the same time, it is likewise not surprising that Thomas's melancholy goes hand-in-hand with beauty. This combination occurs often in his poetry. (And beauty was absolutely real for Thomas -- it was not a poetic conceit.) But enough. Here is the poem.
The green elm with the one great bough of gold
Lets leaves into the grass slip, one by one, --
The short hill grass, the mushrooms small milk-white,
Harebell and scabious and tormentil,
That blackberry and gorse, in dew and sun,
Bow down to; and the wind travels too light
To shake the fallen birch leaves from the fern;
The gossamers wander at their own will.
At heavier steps than birds' the squirrels scold.
The rich scene has grown fresh again and new
As Spring and to the touch is not more cool
Than it is warm to the gaze; and now I might
As happy be as earth is beautiful,
Were I some other or with earth could turn
In alternation of violet and rose,
Harebell and snowdrop, at their season due,
And gorse that has no time not to be gay.
But if this be not happiness, -- who knows?
Some day I shall think this a happy day,
And this mood by the name of melancholy
Shall no more blackened and obscured be.