Pear Fibrecap

Pear Fibrecap is one of the aromatic members of Inocybe, distinguished from the earthy-smelling majority by a powerful sweet fruity scent likened to ripe pears or pear drops. Older literature knows it as Inocybe pyriodora, a name that refers directly to that odour, while fraudans is the currently accepted epithet.

Beyond the scent, the species is marked by a pale start and a red finish: the cap and stipe begin cream to pale ochre-buff and progressively flush rusty red or brick where they are bruised, handled or simply age. A mature troop can therefore contain fruitbodies ranging from almost white to strongly reddened, which is confusing until the pattern is recognised.

It is a comparatively robust fibrecap of broadleaf woodland on richer, often calcareous soils, forming mycorrhizal partnerships with beech and oak, and belongs to the smooth-spored group of the genus.

Cap

3–8 cm across, convex to bell-shaped with a broad low umbo, expanding with age. Initially cream, straw or pale ochre-buff, the surface is dry and finely radially fibrillose, becoming coarsely fibrous and splitting at the margin as it expands. Bruised or ageing areas turn a distinct rusty-red, brick or brownish-red, so older caps may be extensively reddened.

Gills

Adnexed, crowded, whitish to pale cream when young, maturing through clay-buff to dull greyish-brown. The edges are paler and finely fringed, and often become spotted reddish-brown where damaged.

Stipe

4–9 cm tall and 6–15 mm thick, cylindrical or slightly clavate at the base, without a rimmed bulb. Whitish at first, it flushes reddish-brown from the base upward with age and handling, and is longitudinally fibrillose with a pruinose apex. No ring is present.

Flesh and spore print

Flesh is white, reddening slowly where cut or exposed, particularly in the stipe. The odour is strong, sweet and fruity, recalling ripe pears, and is the single most useful field character. The spore print is snuff-brown; spores are smooth and almond-shaped.

Pear Fibrecap grows from soil in deciduous and mixed woodland, favouring beech and oak on neutral to calcareous, moderately rich ground. It also occurs with hornbeam, lime and hazel, and appears in old parkland and wooded churchyards with mature broadleaf trees. Shaded path edges, banks and areas of thin litter over loam are typical spots.

Fruitbodies appear from late summer through autumn, singly or in small scattered groups, occasionally in loose troops. The species is widespread across Europe and reported from temperate North America, though generally less common than the smaller fibrecaps.

Like other members of its genus this is an ectomycorrhizal fungus, forming a hyphal sheath around the fine feeder roots of its broadleaf hosts. The fungal network scavenges nitrogen and phosphorus from soil and litter and delivers them to the tree in exchange for carbon fixed in the canopy, while also buffering the roots against drought.

The strong fruity aroma is produced by volatile esters released as the fruitbody matures and may play a part in attracting fungus gnats and beetles that assist in dispersing spores. The progressive reddening of cut and bruised flesh reflects the oxidation of pigment precursors in the tissue, a reaction shared with a small group of related fibrecaps.

Inocybe corydalina, the Greenflush Fibrecap, has a comparable aromatic odour and pale ochre-buff colouring but shows a distinct blue-green flush over the cap centre and a more bulbous stipe base, and it reddens far less. Inocybe rimosa is more strongly conical, warmer straw-ochre, and neither reddens nor smells fruity.

Inocybe erubescens is similarly reddening but is stockier, whiter when young and reddens more intensely and rapidly, with a shorter, thicker stipe. Hebeloma sinapizans and relatives share the pale clay tones but have smooth, slightly greasy caps, no radial fibre splitting, and a radish rather than pear-like odour.