Old Man of the Woods

Old Man of the Woods (Strobilomyces strobilaceus, also published as S. floccopus) is one of the few boletes that can be named from a single glance at a photograph. Its cap is not smooth but broken into coarse, upstanding, pyramidal scales of sooty grey-black set against a paler woolly ground, giving the whole mushroom the look of a scorched pine cone or a grizzled grey head, which is where both its common and scientific names come from.

The genus Strobilomyces sits in its own family, Boletaceae subfamily Strobilomycetoideae, and is defined by this shaggy scaly construction combined with a dark spore print and ornamented, often reticulate spores. The genus is most diverse in tropical Asia; the temperate northern hemisphere holds only a couple of species.

It is nowhere abundant. Typically it appears singly or in twos and threes, scattered across warm broadleaved woodland, and in many regions it is regarded as a notable find. Old specimens dry and blacken in place, persisting as stiff, sooty, cone-like husks long after most soft boletes have collapsed.

Cap

5-15 cm across, hemispherical then convex, and entirely covered in coarse, thick, overlapping woolly scales that stand up in blunt pyramids, especially toward the centre. The scales are dark grey, blackish-brown or nearly black; between them the paler whitish-grey surface shows through. Soft veil remnants usually hang from the cap margin as a ragged fringe.

Pores

The tube layer is whitish to pale grey in young specimens, darkening through grey to almost black at maturity. Pore mouths are relatively large and angular. Bruising the pore surface produces a two-stage reaction: first a distinct reddish flush, then a slow change to blackish. Tubes are adnate to slightly depressed at the stipe.

Stipe

6-15 cm tall and 1-3 cm thick, cylindrical or slightly tapering, and shaggy or woolly over most of its length in the same dark grey-black tones as the cap. There is usually a coarse ring zone or a shaggy collar where the veil has torn, and the upper stipe may be finely grooved or reticulate. The base is often slightly swollen and matted with dark mycelium.

Flesh & spore print

The flesh is white and firm. Cut surfaces turn pink to orange-red within a minute or two, then darken through grey to black over the following several minutes, a reliable two-step reaction. The spore print is very dark: blackish-brown to black, unusual among boletes, which typically drop olive or ochre spores.

Strobilomyces strobilaceus is ectomycorrhizal and grows on the ground in broadleaved and mixed woodland, most often with oak and beech, and also recorded with hornbeam, sweet chestnut, birch and occasionally conifers. It favours warm, well-drained slopes and prefers acidic to neutral soils, appearing along woodland paths, on mossy banks and in leaf litter under mature trees.

The season runs from midsummer into autumn. In Europe it is a thinly and patchily distributed species, more frequent in the warmer south and central regions and scarce or absent in the north; in eastern North America a closely related and rather commoner shaggy-capped species occupies similar oak and beech woodland. The genus reaches its greatest diversity in subtropical and tropical Asia.

Like other boletes it forms ectomycorrhizas, sheathing host root tips and extending hyphae into the litter and soil to gather mineral nutrients and water in exchange for carbon. Its patchy occurrence and preference for long-established broadleaved stands make it a useful indicator of mature, undisturbed woodland with continuous tree cover.

An unusual ecological trait is the durability of the fruiting body. Where most boletes are soft and are reduced to slime within days, Strobilomyces dries in place, blackening and hardening into a stiff, persistent structure that can be found weeks or even months after it emerged, continuing to shed its dark spores slowly through that period. This drought-tolerant construction is unusual in the family and matches its preference for warm, sometimes seasonally dry woodland.

Strobilomyces confusus (recognised by some authors and widespread in eastern North America and Asia) is extremely similar but has smaller, finer, stiffer and more erect scales rather than the soft, coarse, woolly pyramids of S. strobilaceus, and its spores are differently ornamented. No other temperate bolete combines a shaggy black-scaled cap with a black spore print.

From above, Scaly Tooth (Sarcodon imbricatus) can look superficially similar with its coarsely scaled brown cap, but its underside is covered in spines rather than tubes, and its scales are flat and brown rather than upstanding and sooty. Certain dark, scaly Leccinum species are separated by their smooth caps and stipes roughened only by small scabers, plus an ochre-brown spore print. Woolly-capped Agaricus and Lepiota species have true gills beneath and would never show a tube layer.