Xylaria polymorpha Dead Man's Fingers
In Xylaria polymorpha the fungus produces a cluster of large, hard, black stromata. Each stroma can be about the size and shape of a finger. However, there is a wide variation in shape and size hence the species name polymorpha (many morphological forms). Inside the stroma has a chalk white context of pseudoparenchyma. This is a storage reserve of nutrients and water required for reproduction. The fruitbodies are perithecia. These are embedded in the pseudoparenchymatous matrix and in section (right micrograph) you can see the perithecia around the perimeter of the stroma. The mouth (ostiole) of each perithecium sticks a little bit out giving the surface of the stroma a pimply appearance. As this is a very thin section only a few microns thick then only a few of the perithecia have been cut at the central position, most are cut off centre and a few are cut just at the ebdge of the perithecial and appear as tiny ovals.