# Cerioporus squamosus

Cerioporus squamosus, synonym Polyporus squamosus, is a basidiomycete bracket fungus, with common names including dryad's saddle and pheasant's back mushroom. It has a widespread distribution, being found in North America, Eurasia, and Australia, where it causes a white rot in the heartwood of living and dead hardwood trees.

## Taxonomy

The species was first described scientifically by British botanist William Hudson in 1778, who named it Boletus squamosus. It was given its current name in 1886 by Lucien Quélet but is still widely known by the Elias Magnus Fries name Polyporus squamosus.

### Etymology

Squamosus comes from the Latin squamosus meaning covered with scales or scaly, referring to the signature dark brown scales found on the mushroom's cap.
The name "dryad's saddle" refers to creatures in Greek mythology called dryads who could conceivably sit and rest on this mushroom, whereas the pheasant's back analogy derives from the pattern of colors on the bracket matching that of a pheasant's back.

## Description

Dryad's saddle is an annual mushroom commonly found attached to dead logs and stumps or on living hardwood trees at one point with a thick stem. Generally, the fruit body is round and between 8–30 centimetres (3–12 inches) across – exceptionally 60 cm (24 in) – and up to 10 cm (4 in) thick. The body can be yellow to brown and has "squamules" or scales on its upper side. On the underside one can see the pores that are characteristic of the genus Cerioporus; they are made up of tubes packed together closely. The tubes are between 1 and 12 mm (1⁄16 and 1⁄2 in) long. The stalk is 3–12 cm (1–4+1⁄2 in) long and 1.5–3.5 cm (1⁄2–1+1⁄2 in) thick. The mushroom's smell resembles that of watermelon rind.
The fruit body produces a white spore print. The spores are 11–15 x 4–5 μm and are long and smooth ellipsoids. They can be found alone, in clusters of two or three, or forming shelves. Young specimens are soft but toughen with age. It is particularly common on dead elm and is also found on living maple trees.

### Similar species

In Polyporus tuberaster, the cap is rounder and the stipe more central, with the scales only dark at the tip.

## Distribution and habitat

This organism is common and widespread, being found east of the Rocky Mountains in the United States (April–October) and over much of Europe (July–November). It is also found in Asia and Australia. It commonly fruits in the spring, occasionally during autumn, and rarely during other seasons. Many mushroom hunters will stumble upon substantially sized mushroom this when looking for morels during the spring as both have similar fruiting times.
The species plays an important role in woodland ecosystems by decomposing wood, usually elm, silver maple, or box elder but is occasionally a parasite on living trees. Other tree hosts include ash, beech, horse chestnut, Persian walnut, lime, maple, planetree, poplar, magnolia, and willow.

## Uses

The species is edible when young and cooked. Specimens can become infested with maggots and become firm, rubbery and inedible as they mature. Cookbooks dealing with preparation generally recommend gathering these while young, slicing them into small pieces and cooking them over a low heat.
Some people value the thick, stiff paper that can be made from this and many other mushrooms of the genus Cerioporus.

## Gallery

* Polyporus squamosus
* Forming "shelves" on the side of a tree
* Growing on ground
* Shelf growing on tree
* Bird's eye view of shelf
* Growing on an elder (Sambucus nigra) in Scotland
* Pores
* Secretion
* Close-up of secretion