Hexagonal-pored Polypore

The Hexagonal-pored Polypore is named for the single feature that makes it unmistakable: a pore layer so coarse that individual openings look like the cells of a honeycomb, elongated along the radius of the cap. Few temperate fungi have pores this large, and none combine them with the same thin, orange-tinted, scaly cap.

The species has moved through several genera, having been known as Polyporus alveolaris and Favolus alveolaris before molecular work established Neofavolus for it and a few relatives within the Polyporaceae. Its nearest kin are the other stalked and semi-stalked white-rotting polypores of branch wood, and it fruits at much the same time of year as the Spring Polypore.

It is a small and easily overlooked fungus, usually found by turning over fallen twigs and branches in spring woodland. The bright orange of a fresh cap fades quickly to buff, so faded specimens are recognised by pore structure alone, which fortunately is unambiguous.

Cap

The cap is 1 to 8 cm across, circular to kidney-shaped or fan-shaped depending on how it is attached, and thin, often only 2 to 5 mm thick. When young and fresh it is a striking orange to reddish-orange or salmon-orange, dressed with fine darker fibrillose scales; with age and sun exposure it fades to yellowish-tan, buff or almost whitish, and the scales become inconspicuous. The margin is thin, often inrolled when young, and may split radially in dry weather.

Pores

The underside is diagnostic. Pores are very large, roughly 0.5 to 3 mm across, sharply angular to hexagonal, and arranged in radiating rows so that they are noticeably stretched from the point of attachment outward. The surface is white to cream, ageing pale buff, and the pore layer runs down onto the stem where one is present. Tube walls are thin and often become toothed or ragged in old specimens.

Stipe

The stipe is short and inconspicuous, 0.5 to 2 cm long, lateral or strongly off-centre, and sometimes almost absent so that the cap appears sessile and attached directly by one edge. It is whitish to buff and smooth to finely scurfy.

Flesh and spore print

The flesh is thin, white and tough, drying hard and papery, with no colour change on cutting. The spore deposit is white.

This polypore lives on dead hardwood branches, particularly the smaller fallen limbs and attached dead twigs that accumulate after storms and canopy thinning. It has a strong preference for a range of broadleaves, with maple, hickory, beech, hop-hornbeam, ash, oak, cherry and elm all frequent substrates, and it favours wood that is recently dead and still firm with the bark attached.

Fruiting is concentrated in spring and early summer, often overlapping with the Spring Polypore, and in wetter seasons it may reappear into autumn. Fruit bodies frequently occur in scattered groups or short rows along the underside of a single branch. The species is common and widespread across eastern and central North America and occurs through Europe and temperate to subtropical Asia, in deciduous and mixed woodland, riverside woods and shaded hedgerows.

Neofavolus alveolaris is a saprotroph causing white rot, breaking down lignin and cellulose in small-diameter deciduous branch wood so that the colonised material bleaches, softens and becomes fibrous. It is typically an early to mid-stage coloniser, arriving on branches that have recently fallen or died in the canopy.

The unusually wide pores are thought to relate to its thin, quick-drying fruit bodies: broad tubes shed spores readily in moving air and are less prone to clogging when the fruit body repeatedly dries and rewets. In woodland nutrient cycling the species is part of the guild that processes the constant rain of branch litter, converting it into soft rotten wood and eventually humus, and providing feeding and shelter substrate for fungus-associated invertebrates.

Lentinus arcularius is the most similar, sharing large angular pores and a scaly cap, but its pores are smaller and less strongly radially elongated, its cap is tan to yellow-brown rather than orange and carries a distinct fringe of coarse marginal hairs, and its stipe is slender and central rather than short and lateral. Lentinus brumalis has much smaller round pores and a plain grey-brown velvety cap.

Cerioporus squamosus has similarly angular radial pores but is enormously larger, with a broad kidney-shaped cap bearing coarse concentric brown scales and a thick lateral stipe with a black base. Various Trametes species can overlap in cap colour when faded but have small round to angular pores of several per millimetre and are usually distinctly zoned and sessile.