It grows as stiff, half-moon shelves stacked one above another along a dead root, each from a palm to a forearm across and two fingers thick, its upper side banded in dull browns and greys like the rings of a cut log, its underside pale cream and fine-pored. Old shelves turn woody and cracked; young ones at the edge of a stack are softer and paler. It has a woody, mushroomy smell, and in the gloam it looks like a growth of the root itself.

It grows on dead root and the dead fringes of living root in still, damp air, and it is commonest where the living root has thinned to dead strands in the lower hollows and the fungal darks. Wild stands lie beyond the beds, on the side ways and towards the end of the Known Ways.

A shelf grows a new layer each root-year and can live for many years on a single dead root, until the root is eaten through and falls. It spreads by a fine brown spore that dusts the stone below each stack.

Only the soft, young edge is eaten. It is sliced thin, soaked, and boiled long, or dried and ground into the meal of fungus cakes when nothing better is left; it fills the belly and gives little. Gatherers walk the side ways in hard times to cut it, and that walking is its danger, since the wild stands lie where nothing is kept and a way can be struck off the reckoning. A house that has to send its children for rot-shelf is a house in trouble, and everyone knows it.

"Rot-shelf seasons" are hungry years in Dark Elf speech, and old people count their lives by them. A house will not gather rot-shelf from another house’s dead root without leave, since the root counts in chamber-right; in the worst years that rule is argued over and sometimes broken. Some Dark Elf households cut one shelf in a good year and keep it dry above the door, so that the house remembers.

In the worst years houses have come to blows over a dead root’s shelf, and some of the oldest feuds in the Roothollows are said to have begun in a rot-shelf season.