From the SAS Survival Guide to the contemporary art practise of Urbanibalism foraging is at least in part considered as a source of famine food, a practise reinvented as the last resort when all other avenues of acquiring food have broken down. Surely every enduring culture must have produced songs, poem and stories that laments the sorrows of hunger and remembers the kind of grasses and weeds that sustained the people through the ordeal. I welcome suggestions to more because the only example I can think of that uses foraging (picking young fern shoots) both as an indication of bad fortune and as an indicator of time passing (grubbing old fern shoots) is the poem that opens Ezra Pound's Cathay (1915), his legendary collection of 'translations from the Chinese'. Song of the Bowman of Shu was written in the 11th century by Bunno, the Japanese name of Wen-Wang, the King Wen of the I Ching. Here is some additional stuff about the edibility of ferns.
SONG OF THE BOWMAN OF SHU
Here we are, picking the first fern-shoots
And saying: When shall we get back to our country?
Here we are because we have the Ken-nin for our foemen,
We have no comfort because of these Mongols.
We grub the soft fern-shoots,
When anyone says "Return," the others are full of sorrow.
Sorrowful minds, sorrow is strong, we are hungry and thirsty.
Our defence is not yet made sure, no one can let his friend return.
We grub the old fern-stalks.
We say: Will we be let to go back in October?
There is no ease in royal affairs, we have no comfort.
Our sorrow is bitter, but we would not return to our country.
What flower has come into blossom?
Whose chariot? The General's.
Horses, his horses even, are tired. They were strong.
We have no rest, three battles a month.
By heaven, his horses are tired.
The generals are on them, the soldiers are by them.
The horses are well trained, the generals have ivory arrows and
quivers ornamented with fish-skin.
The enemy is swift, we must be careful.
When we set out, the willows were drooping with spring,
We come back in the snow,
We go slowly, we are hungry and thirsty,
Our mind is full of sorrow, who will know of our grief?