King Bolete Boletus edulis and the porcini mushrooms of the Pacific Northwest
The king bolete (Boletus edulis) is among the world’s most prized wild mushrooms. The Pacific Northwest has several members of the porcini group: B. edulis (including var. grandedulis), the spring king (B. rex-veris), the fib king (B. fibrillosus), the queen bolete (B. mottiae, formerly B. regineus) and the white king (B. barrowsii). This guide focuses on the three most often found in PNW conifer forests: the king, spring king and fib king.
They differ in season and habitat. The king bolete has two distinct habitats: Sitka spruce forest on the coast, and higher-elevation conifer forest in the Cascades; the spring king fruits after snowmelt on the east side of the Cascades; and the fib king is found widely under Douglas-fir and true firs but seldom in quantity. Knowing which species fruits when and where is the key to finding them.
Scout Bolete Habitat on Forayz
Use ecoregion data, soil moisture, and elevation layers to find productive mountain conifer forests. Free with a Forayz account.
Master King Bolete ID on Your Phone
The PNW Boletes deck in ForayzU covers king boletes (Boletus edulis & rex-veris), Suillus, Leccinum, and the look-alikes to avoid — swipeable photo flashcards, no subscription.
Porcini Around the World: Common Names by Country
Boletus edulis is prized across the Northern Hemisphere, and nearly every mushroom-loving culture has its own name for it. If you arrived here searching in another language, this is the same mushroom — and the identification below applies worldwide.
Italy · France · UK
porcino / porcini (Italian) · cèpe / cep de Bordeaux (French) · penny bun (English)
Germany · Austria · Switzerland
Steinpilz (plural Steinpilze)
Scandinavia
Karl Johan / karljohansvamp (Swedish, Norwegian) · herkkutatti (Finnish)
Poland · Czechia · Slovakia
borowik szlachetny / prawdziwek (Polish) · hřib smrkový (Czech) · hríb smrekový (Slovak)
The Balkans
манатарка / manatarka (Bulgarian) · вргањ / vrganj (Serbian, Croatian, Macedonian) · jurček / goban (Slovenian)
Russia · Ukraine
белый гриб (belyy grib, “white mushroom”) · боровик (borovik)
The Baltics
baravykas (Lithuanian) · baravika (Latvian)
Türkiye
bolet mantarı / ayı mantarı
Japan · China
ポルチーニ (poruchīni) / ヤマドリタケ · 美味牛肝菌 (Chinese, “delicious ox-liver fungus”)
Vietnam
nấm gan bò (“ox-liver mushroom”)
Whatever you call it, the field marks are the same. This guide focuses on the three porcini species of the Pacific Northwest — but a King Bolete is a King Bolete the world over.
Identifying King Boletes
The three species share the same basic field marks. The details below are for B. edulis; the species cards further down give the differences.
- Cap: 5–20 cm (up to 35), bun-shaped becoming broadly convex; usually creamy beige or tan to light brown, sometimes darker or orange-brown; dry to greasy or thinly sticky
- Pores: Small and round, stuffed with white tissue when young; white, becoming creamy yellow and then yellowish olive; do not bruise blue. (In var. grandedulis they turn reddish to bronze in age.)
- Stem: 8–17 cm tall, 2–5 cm thick at the top (up to 8); club-shaped when young, often becoming longer and slimmer; whitish, with a fine to coarse white reticulation (net-like pattern), most pronounced near the top
- Flesh: White, firm, does not change color when cut
- Spore Print: Olive-brown
- Odor and taste: Odor indistinct; taste mild to sweet or nutty
The Reticulation Test
The raised, net-like pattern on the upper stem is a key feature of porcini: if the stem is smooth or scabrous (rough with dark dots, like Leccinum), it is not a king bolete. But a net pattern alone doesn’t confirm one. The toxic red-pored bolete has a red net on its stem, and some bitter boletes are reticulated too. Confirm with white, non-staining flesh, pores that don’t bruise blue, and a mild taste.
What King Boletes Do NOT Have
Knowing what to rule out is just as important as knowing what to look for. A true porcini won’t show any of the following:
- Blue bruising: If the pores or flesh turn blue when cut or pressed, stop. You may have a Rubroboletus (red-pored boletes) or another species. Some blue-staining boletes are toxic.
- Red pores with blue staining: Deep red pores that stain blue-black point to the red-pored bolete (Rubroboletus pulcherrimus), which grows under conifers in the PNW and is extremely toxic. R. eastwoodiae (California Satan’s bolete) is a similar species found with oak. Note that old var. grandedulis pores can turn reddish-bronze, but they don’t stain blue.
- A truly slimy cap: A king bolete’s cap can be greasy or thinly sticky, but a thick, slimy cap suggests Suillus. These are edible but not porcini, and most foragers find them less desirable.
- Scabrous stem (rough dark dots): Dark scabers on the stem point to Leccinum species. Also edible, but a different genus entirely.
- Bitter taste: A bitter taste (spit it out) points to Caloboletus, which also stain blue. C. frustosus is extremely bitter; the common red-stemmed C. rubripes is only mildly bitter. They are not recommended: minor stomach upset has been reported from Caloboletus.
Not sure what you’ve found? Our Bolete Finder tool walks you through the identification step by step using cap color, pore color, bruising, and stem texture to narrow down your species. For a broader overview of toxic mushrooms in the Pacific Northwest, see our dedicated page.
PNW Porcini Species
These three are the porcini most often found in PNW conifer forests. They share the reticulated stem and are all good edibles, but differ in timing, region and tree associations.
King Bolete
Boletus edulis
The classic porcini, with two distinct habitats. On the coast it fruits in a flush in early to mid fall under Sitka spruce. In the Cascades it fruits at higher elevations with true firs, and on the east slopes with spruce, in summer and early fall. Favors forest edges, road and trail sides, and openings.
Mycorrhizal Choice Edible FallSpring King
Boletus rex-veris
Fruits a few weeks after snowmelt in spring, continuing into summer at higher elevations. Mainly an east-slope species of fir and pine forest; rare west of the crest outside rain-shadow pockets. Pinkish to reddish-brown cap with a white bloom when young; often pushes up under the duff.
Mycorrhizal Choice Edible SpringFib King
Boletus fibrillosus
Dark brown to honey-brown cap with a velvety to matted-fibrillose surface (the king bolete’s is paler and smoother), and a brownish, reticulated stem with a pale, often rooting base. Grows with conifers, mainly Douglas-fir and true firs; found widely but seldom in quantity. Late summer through fall into early winter. Edible and very good.
Mycorrhizal Edible FallWhen to Hunt: Season & Timing
Timing depends on species and region: snowmelt for the spring king on the east side, and fall rain for the king bolete, both on the coast and in the mountains.
| Season | Species | Where | What to Watch |
|---|---|---|---|
| Spring | Spring King (B. rex-veris) | East side of the Cascades, fir and pine | A few weeks after snowmelt; often under the duff at first |
| Summer | Spring King (B. rex-veris) | Higher elevations, east side | Continues upslope as the snow recedes |
| Late summer – early fall | King Bolete (B. edulis), Fib King (B. fibrillosus) | Higher elevations with fir; east slopes with spruce | Most plentiful after summer rain or a warm, wet fall |
| Early – mid fall | King Bolete (B. edulis), Fib King (B. fibrillosus) | Coast, with Sitka spruce | The king bolete’s coastal flush; fib king continues into early winter |
Soil Moisture Is Your Best Predictor
In fall, king boletes follow the rain; in the mountains they are most plentiful after summer rain or a warm, wet fall. In spring, spring kings follow snowmelt. Tracking soil moisture and snow cover tells you more than a calendar date.
Track Soil Moisture & Snow Cover
Forayz shows real-time soil moisture, soil temperature, snow cover, and recent rainfall — the exact data you need to time bolete hunts. Free with a Forayz account.
Where to Look: Habitat & Trees
All three are mycorrhizal, forming underground partnerships with living tree roots, but they partner with different trees:
- Sitka spruce (coast): One of the king bolete’s two habitats, fruiting in early to mid fall, including in coastal dunes.
- True firs (Abies): The king bolete’s other habitat, at higher elevations in the Cascades in summer and early fall; spring king on the east side, and fib king.
- Pine: Spring king in east-side pine forests; var. grandedulis with shore pine in coastal dunes.
- Douglas-fir: The fib king’s main host, with true firs.
King boletes favor forest edges and disturbed ground: meadow edges, road and trail sides, and forest openings. The queen and white kings grow mainly with hardwoods, including planted oaks in urban areas.
Cooking & Preserving
Porcini are prized for their rich flavor, large size and firm texture.
- Sautéed: Slice thickly and cook in butter over medium-high heat. Don’t crowd the pan; brown well on both sides.
- Dried: Drying concentrates the flavor. The tubes of older specimens are soft but full of flavor, and many people dry them separately as a rub or a base for stock and gravy.
- Frozen: Sauté first, then freeze.
- Bug check: Boletes are notorious for insect larvae. Slice every mushroom from cap to base and inspect. Trim out wormy sections — partial salvage is normal and expected with porcini.
Use the Bolete Finder
Found a bolete but not sure if it’s a king? Our Bolete Finder tool uses cap color, pore color, bruising reaction, and stem texture to help you narrow it down. It covers all the common PNW bolete genera including Boletus, Suillus, Leccinum, Xerocomellus, and Caloboletus.
Find Your First King Bolete with Us
Habitat, timing, and the look-alikes worth knowing — learned on the ground instead of from a screen. Our last evening intro class of the fall is in Bellevue, and small-group guided tours run in the Cascades through November.
Sources: Mushrooms of Cascadia (Siegel & Schwarz, 2024); MycoMatch (© Ian Gibson), a compilation of published descriptions through which most other field-guide authors named here are quoted.