The adjective hygrophanous refers to the color change of mushroom

Mushroom

A mushroom is the fleshy, spore-bearing fruiting body of a fungus, typically produced above ground on soil or on its food source. The standard for the name "mushroom" is the cultivated white button mushroom, Agaricus bisporus; hence the word "mushroom" is most often applied to those fungi that...

 tissue (especially the pileus

Pileus (mycology)

The pileus is the technical name for the cap, or cap-like part, of a basidiocarp or ascocarp that supports a spore-bearing surface, the hymenium. The hymenium may consist of lamellae, tubes, or teeth, on the underside of the pileus...

 surface) as it loses or absorbs water, which causes the pileipellis

Pileipellis

thumb|300px||right|The cuticle of some mushrooms, such as [[Russula mustelina]] shown here, can be peeled from the cap, and may be useful as an identification feature....

 to become more transparent when wet and opaque when dry.

When identifying hygrophanous species, one needs to be careful when matching colors to photographs or descriptions, as color can change dramatically soon after picking.

Genera that are characterized by hygrophanous species include Agrocybe

Agrocybe

Agrocybe, including edible fungi such as the Agrocybe cylindracea, is a genus of mushroom with similar characteristics to the Tricholoma matsutake, Agrocybe aegerita and Agrocybe parasitica. Some are poisonous mushrooms...

, Psathyrella

Psathyrella

Psathyrella is a large genus of about 400 fungi, and is similar to the genera Coprinellus, Coprinopsis, Coprinus and Panaeolus, usually with a thin cap and white or yellowish white hollow stem. But the caps do not self digest as do those of Coprinellus and Coprinopsis. Some also have brown spores...

, Psilocybe

Psilocybe

Psilocybe is a genus of small mushrooms growing worldwide. This genus is best known for its species with psychedelic or hallucinogenic properties, widely known as "magic mushrooms", though the majority of species do not contain hallucinogenic compounds...

, Panaeolus

Panaeolus

Panaeolus is a genus of small, black-spored, saprotrophic agarics. The word Panaeolus is Greek for "all variegated", alluding to the spotted gills of the mushrooms produced.- Characteristics :...

, and Galerina

Galerina

Galerina is a genus of small brown-spored saprobic mushrooms, with over 300 species found throughout the world, from the far north to remote Macquarie Island in the Southern Ocean. Species are typically small and hygrophanous, with a slender and brittle stem. They are often found growing on wood,...

.

External links

• IMA Mycological Glossary: Hygrophanous
• Wisconsin Mycological Society: Psathyrella Photographs of Psathyrella, a mushroom with a strongly hygrophanous pileus.