Fluted Bird’s Nest (Cyathus striatus)

The Fluted Bird's Nest (Cyathus striatus) is a tiny, cup-shaped fungus that looks like a miniature nest holding a few silvery eggs. The outside of the cup is shaggy and rusty brown, while the inside is silvery-grey and marked with fine vertical grooves. Young cups are sealed by a thin white lid, which tears open to show the lens-shaped spore packets (peridioles) inside, each tethered to the wall by a thread.

It is widespread and fairly common in the UK, usually found in troops on rotting wood and on wood chip in gardens and parks. Fruiting is most obvious from late summer to the end of the year, and old cups can last into winter.

The grooved inner wall separates it from similar nest fungi. Cyathus olla has a smooth inner wall, Crucibulum laeve has a pale yellowish cup with a smooth interior, and the dung-loving Cyathus stercoreus has much smaller peridioles and a less flared rim. Bird's nest fungi are too small to be of any use as food and should not be eaten.

Spore Print

Season

J

F

M

A

M

J

A

S

O

N

D

Native

unknown

Distribution

Widespread and fairly common

Habitat

Typically occurs in troops on wood or wood chips

Etymology

Cyathus comes from the Greek kyathos, meaning a drinking cup or ladle, a good match for the small cup-shaped fruiting body. The epithet striatus is Latin for striped or grooved, and refers to the fluted ridges lining the inside of the cup.

Fruiting Body

A deep, goblet-shaped cup, 8-15mm tall and 6-8mm wide, with a shaggy, rusty brown outer surface covered in coarse hairs. When young the cup is closed by a thin white membrane (the epiphragm), which splits open to reveal the inner chamber. The inner wall is silvery-grey and ridged or fluted lengthwise, and holds 12-16 pale grey, lens-shaped spore packets (peridioles), each anchored to the wall by a fine thread called a funicular cord.

Colour

Spores

The spores are colourless, smooth and thick-walled, shaped like a rounded oblong or ellipse. They are formed inside the peridioles rather than being shed from gills, so there is no spore print. They are released only when raindrops splash the peridioles out of the cup. They do not stain with iodine (inamyloid).