Fluted bird's nest

Description

The fluted bird's nest is a tiny fungus that looks like a little nest with eggs. The cup is usually 1–2 cm tall and about 1 cm wide. On the outside it is rusty brown to almost black and shaggy, while inside it is smooth, silvery and distinctly grooved. In mature specimens, grey, flat "eggs" (peridioles) 1–2 mm in size lie inside and contain the spores. A young cup is covered by a thin membrane, which eventually ruptures.

It grows in summer and autumn, solitary or in groups, on rotting twigs, pieces of wood, leaves and wood chips, usually in moist thickets and forests, also in parks and under shrubs. In Poland it is common.

It is distinguished from similar cups by its shaggy outer surface and grooved interior; in the grey bird's nest (Cyathus olla) the interior is smooth. It is an inedible fungus, collected at most out of curiosity.

Identification features

Cap

No cap in the strict sense; the fruiting body is cup-shaped (peridium), vase-shaped or an inverted cone, usually 7–20 mm tall and 6–10 mm wide (exceptionally up to 1.5 cm). The outer surface (exoperidium) is rusty brown, brown to almost black, sometimes greyish beige, shaggy or hairy, with the hairs pointing mainly downwards. The margin may be slightly turned outwards. The interior (endoperidium) is smooth, hairless, distinctly longitudinally grooved and silvery shiny. Young fruiting bodies are closed by a thin membrane (epiphragm), hairy like the outer surface; at maturity it ruptures and falls away, exposing the peridioles.

Hymenophore (underside of the cap)

No gills or tubes. The hymenium is contained in peridioles, tiny lens-shaped or disc-shaped bodies lying in the cup like eggs in a nest. The peridioles are about 1–2 mm in diameter, grey or greyish brown (dark or dull grey while still covered by a thin layer, the tunica), and may look angular from the pressure of neighbouring ones. Each peridiole is attached to the cup wall by a cord (funiculus) made up of a basal part, a middle part and a sheath (purse), inside which lies a coiled thread with a sticky hapteron. The dry cord is brittle; when wet it is highly extensible.

Stem

No true stem. The cup is attached to the substrate by a compact mass of hyphae (emplacement), usually 8–12 mm in diameter, often containing small fragments of the substrate.

Flesh

No typical flesh; the fruiting body is small, thin-walled and leathery. Colour changes, smell and taste: no data. Should not be tasted.

Spore print and spores

Spores colourless (hyaline), elliptical to ovoid, smooth, with a notch at one end; size about 15–22 × 8–12 µm (descriptions give different ranges). Within a peridiole the spores form on basidia; spore print colour: no data.

Habitat and distribution

Ecology. Saprotroph. Grows on dead wood of broadleaved and coniferous trees, on small twigs and other woody debris, on leaves and plant remains, also on wood-chip mulch in parks and under shrubs. It appears more readily in moist, shallow depressions than on raised ground. Spores are dispersed by the "splash cup" mechanism: a raindrop striking at a suitable angle ejects the peridioles from the cup, the cord unrolls, and the sticky hapteron wraps around a thin stem or twig. The peridioles decay over time or may be eaten by herbivorous animals and dispersed in their droppings.

Distribution. Cosmopolitan species, recorded on every continent except Antarctica, including Asia, Europe, the Americas and New Zealand; widespread in the temperate zone. In Europe it reaches about 64° latitude in the north. Common in Poland, in moist thickets and forests. Not legally protected in Poland.

Fruiting. Summer and autumn, in warm seasons until early winter; fruiting bodies solitary or in groups, often in clusters on small twigs.

What can it be confused with?

• Cyathus olla (grey bird's nest) — Silky-fibrous on the outside rather than shaggy; inside without grooves.
• Cyathus stercoreus — Grows on dung; the inside of the cup is not grooved.

Never rely on a single feature. If you are not sure — do not pick it; show the mushroom to a qualified mushroom expert.

Interesting facts

• It was first described by William Hudson in 1778 as Peziza striata; the current genus name was given to it in 1787 by Carl Ludwig Willdenow.
• The English name "splash cups" refers to spore dispersal: a raindrop striking the inside of the cup throws the peridioles some distance away.
• A thrown peridiole trails a cord with a sticky hapteron, which wraps around a twig or stem like the ball on a tether in the game of tetherball.
• Compounds with in vitro antimicrobial activity have been isolated from the fungus: cyathins and striatins; four acids (cyathic, striatic, cyathadonic and epistriatic) were previously unknown.