Short-stemmed Slippery Jack
Suillus brevipes
Also called stubby-stalk, short-stalked bolete
A dark, heavily glutinous pine bolete on a conspicuously short, stout white stalk that lacks both a ring and obvious glandular dots. Common in coastal and montane pine.
Overview
Suillus brevipes is the archetypal squat slippery jack of North American pinewoods. Its species name means 'short foot', and the proportions are the quickest field character: a broad, dark, varnished-looking cap sitting on a stubby white stalk that is often barely longer than the cap is wide.
Within Suillus it falls in the ringless group, but unlike the Weeping Bolete it lacks conspicuous glandular dots on the stalk, at least when young, so the stem appears smooth and clean white before yellowing with age. The very glutinous cap skin peels away readily in a single sheet.
It is one of the most abundant boletes of sandy pine country, from the coastal lodgepole and shore pine forests of the Pacific Northwest to Monterey pine plantings in California and red and jack pine stands in the north and east, often fruiting in vast numbers late in the season.
How to identify it
Cap
4-10 cm across, occasionally larger, convex then flattened. The surface is smooth and heavily glutinous when wet, drying shiny and tacky. Colour is dark chocolate to reddish-brown or nearly blackish-brown when young, fading with age and sun exposure to ochre, tan or dull cinnamon. The skin peels easily.
Pores
Small, round and pale yellow when young, becoming dingy or brownish-yellow with age. The tube layer is adnate, sometimes shallowly decurrent, and can weep slightly in very humid conditions.
Stipe
Distinctly short: usually 2-5 cm tall against a 1-2.5 cm thickness, solid, stout and often slightly swollen. It is white at first, slowly yellowing from the base upwards. There is no ring, and glandular dots are absent or very faint and pale, developing only in age.
Flesh & spore print
The flesh is thick, soft, white to pale yellow, and does not change colour appreciably when cut. The spore print is dull cinnamon to brown.
Where and when it grows
Ectomycorrhizal with hard pines, particularly two- and three-needle species: lodgepole and shore pine, Monterey pine, ponderosa pine, jack pine and red pine. It favours sandy or gravelly soils in open woodland, coastal dune forest and montane pine flats, often fruiting in large scattered troops among needle litter.
The season is mainly autumn, extending into early winter in mild coastal regions where fruiting can continue through December. It is widespread across North America and has been introduced with planted pine to other continents.
Ecological role
Like all slippery jacks, this species forms ectomycorrhizas, enveloping pine root tips in a fungal mantle and running hyphae out into the soil to capture nutrients and water. Its ability to colonise young trees on impoverished sands makes it a common associate of pine plantations and of naturally regenerating stands after disturbance.
Massive late-season fruitings supply an important seasonal resource to slugs, rodents, deer and fungus-breeding flies, and the rapidly decaying fruiting bodies return nutrients to the litter layer. Spore dispersal by mammals that disturb the fruiting bodies contributes to the fungus's rapid spread in new plantings.
Similar species
Suillus luteus has an equally dark glutinous cap but a long stalk bearing a large, persistent membranous ring, with glandular dots above it. Suillus granulatus has a longer stalk conspicuously dotted with brown granules and a paler cinnamon cap that weeps milky droplets when young.
Suillus pungens of the west coast has a mottled cap that begins whitish and olive before turning dingy yellow-brown, together with a strong odour. Suillus tomentosus differs in its dry, finely woolly yellow cap and flesh that stains blue when cut.