What is the meaning of Dead_man's_fingers?

Any of several plants or other organisms with fleshy finger-like structures:

  1. The fungus Xylaria polymorpha;
  2. The soft coral Alcyonium digitatum;
  3. The seaweed Codium fragile;
  4. A shrub or small tree, Decaisnea insignis, with edible fingerlike pods;
  5. The early purple orchid, Orchis mascula.

The fungus Xylaria polymorpha;

The soft coral Alcyonium digitatum;

The seaweed Codium fragile;

A shrub or small tree, Decaisnea insignis, with edible fingerlike pods;

The early purple orchid, Orchis mascula.

The fingerlike gills of a crab.

Source: wiktionary.org