Hexagonal-pored Polypore Identification Guide

First Impression and Setting

This is a small mushroom found by looking down at the debris rather than up at the trunks. Picture yourself in a damp broadleaf wood in late spring, poking through a tangle of fallen sticks and small branches after a wet week. Neofavolus alveolaris shows up as a scatter of little orange-tan fans, each the size of a coin to a matchbox, projecting sideways off dead twigs at knee height or lying against the litter.

The colour is what catches the eye first: fresh caps are a warm orange, apricot or reddish-tan, noticeably brighter than almost anything else on a spring stick. That brightness fades fast, so older specimens are buff, pale tan or nearly white, and a single branch can carry both stages at once.

Then comes the second impression, which is the identification: pick one up and look underneath, and the pores are so large and so obviously six-sided that they can be read without a lens.

The Cap in Detail

Caps are 1-8 cm across, most often 2-4 cm. The outline is fan-, kidney- or shell-shaped, sometimes almost circular in specimens growing on the upper side of a horizontal stick, and often irregularly lobed or wavy at the edge. They are convex at first and flatten out, sometimes becoming shallowly depressed towards the point of attachment.

The surface is dry - never viscid - and covered with fine, flattened, appressed scales and fibrils that lie in radiating lines from the attachment point outward. Under a lens these look like tiny darker orange-brown streaks against a paler ground. On some specimens the scales are dense enough to make the cap look tweedy; on others, especially after weathering, the cap is nearly smooth.

The margin is thin, sharp and often inrolled when young, frequently splitting radially as the cap dries out. In the very thinnest specimens you can see the pore pattern showing through the margin as a faint scalloping.

The Pore Surface: The Diagnostic Feature

Turn it over. This is where the species names itself.

The pore surface is white to cream, sometimes ageing to pale buff or ochre. The pores are enormous by polypore standards: 0.5-2 mm wide, sometimes larger near the stalk, angular and hexagonal, with thin walls, and - this is the key detail - arranged in radiating rows so that the individual pores are elongated along the radius of the cap. The overall effect is of a honeycomb that has been stretched outwards from the point of attachment.

The pore layer is shallow, only 1-3 mm deep, and it runs decurrently down onto the short stalk, so the boundary between cap underside and stipe is a gradual fading rather than a clean line. Near the outer rim the pores often become smaller and more regularly hexagonal; near the centre they stretch into slots.

Look at the pore walls edge-on with a lens: they are thin, entire and pale, not fringed or toothed.

Stipe, Base and Attachment

The stalk is short - usually 0.5-1.5 cm, sometimes almost absent - and set laterally or eccentrically, so the cap projects out from the substrate like a small bracket on a stub. It is white to pale cream at the apex where the pores run onto it, and often dingier or brownish at the very base where it meets the wood.

The base attaches directly to bark or to the exposed wood of the twig, with a small pad of white mycelium. There is no ring, no volva, no bulb and no rooting extension.

Flesh and Colour Change

The flesh is thin - a millimetre or two - white, and tough but pliant, with a leathery, slightly rubbery quality when fresh that becomes hard and brittle on drying. It will bend a long way before it tears.

Cut a cap across and watch: nothing happens. There is no colour change on cutting or bruising, no latex, no gel layer, and no zoning within the flesh. Dried specimens shrink, harden and pale, and they revive somewhat if soaked, holding their shape well enough that old herbarium material is still recognisable by its pores alone.

Taking a Spore Print

Small polypores are stingy printers, so use a fresh, actively growing specimen and give it time. Cut the cap free with the stipe attached, lay it pore-side down on a glass slide or a piece of black card, cover it with a cup, and leave it overnight somewhere cool and out of draughts.

The print is white. Microscopically the spores are the second good confirmation: long, narrow cylinders, smooth, colourless, roughly 9-13 x 3-4 microns - much more elongated than the spores of most small polypores, and non-amyloid. The hyphal system is dimitic, with skeletal hyphae running through the flesh, which is why so thin a mushroom is so tough.

Substrate and Season

Neofavolus alveolaris is a saprotroph of small-diameter dead broadleaf wood. It specialises in fallen twigs, sticks and slender branches from perhaps a finger's width to an arm's width - much smaller material than most polypores bother with - and it is particularly associated with hickory, and also with maple, oak, elm, hornbeam, hop hornbeam, birch and beech. Attached dead branches still up in a tree, recently fallen brush piles and storm-shed limbs are all good places. It does not occur on conifers and it does not grow from soil.

Season is a real character here. It is one of the earliest polypores of the year, appearing in spring - often alongside the first morels and long before the summer bracket flush - and continuing into early summer, with a smaller scattering in autumn in some regions. It is widespread across eastern North America and occurs across Europe and temperate Asia.

Because it fruits on small wood, it tends to appear in troops: find one and you will usually find six more on the same branch.

Separating It From Look-alikes on Structure Alone

Spring polypore (Lentinus arcularius, formerly Polyporus arcularius) is the closest confusion and shares the season and substrate. The distinctions are all structural: its stalk is central, so the cap is circular with a dimple in the middle rather than fan-shaped on a side stalk; the cap is darker brown and more coarsely scaly; the margin carries a fringe of stiff hairs; and while its pores are angular, they are smaller and arranged more evenly rather than in stretched radial rows.

Winter polypore (Lentinus brumalis, formerly Polyporus brumalis) likewise has a central stalk, a greyish to dull brown finely hairy cap, and small round to slightly angular pores that are nothing like a honeycomb. It also fruits in the cold months rather than in spring.

Blushing bracket (Daedaleopsis confragosa) has elongated slot-like pores that can look superficially similar, but it is a sessile bracket with no stalk at all, much thicker and woodier, growing on standing dead willow and birch, and its pore surface reddens where bruised.

Turkey tail and its relatives (Trametes spp.) form stalkless, thin, zoned, often hairy shelves in overlapping tiers with very fine round pores - the pore size alone rules them out immediately.

Mossy maze polypore (Cerrena unicolor) is stalkless, grey-green with algae, and has a maze-like, tooth-fringed pore surface rather than clean hexagons.

Tropical Favolus species have comparable large radial pores, but they are larger, thinner, more translucent and usually white to pale ochre without the orange scaly cap, and they occur outside the temperate range.

Field Sequence

1. Small fan on a dead broadleaf twig, spring or early summer.
2. Orange to tan cap, dry, with fine radiating appressed scales.
3. Underside: big angular hexagonal pores in radiating rows, 0.5-2 mm.
4. Short lateral or off-centre stalk with the pores running down it.
5. Thin, tough, unchanging white flesh.
6. White spore print; long narrow cylindrical spores if you have a scope.