Scaber Stalks Leccinum — the rough-stemmed boletes of PNW forests
Leccinum species are tall, sturdy boletes with dark, rough projections (scabers) on the stem, which set them apart from other PNW boletes. Run a finger down the stalk: scabers feel rough, unlike the smooth or netted stems of most other boletes.
Several species live in the Pacific Northwest, associated with birch, aspen, pine, madrone and other trees (Siegel & Schwarz, Mushrooms of Cascadia). Telling them apart is hard, though. The scientific names used here are unsettled (see Key PNW Species below), so treat species names on this page as working labels.
Find Leccinum Habitat on Forayz
Use forest type overlays and satellite basemaps to locate aspen, madrone, and pine stands — some of the tree partners of Leccinum.
Identification
| Feature | Description |
|---|---|
| Cap | About 4–20 cm across, hemispheric to convex, becoming bun-shaped. Surface dry to suede-like or thinly viscid. Color varies by species: dark brown to gray-brown in the birch species, orange-red to reddish brown in the orange-capped group. |
| Pores | Small and round, whitish to beige at first, then duller and darker as they age. Bruising is slow and brownish or gray-brown. |
| Stem | Tall and solid, roughly 5–20 cm long, club-shaped to nearly equal, whitish to pale gray and covered in scabers (rough projections). In the orange-capped species the scabers start pale and darken with age; in the birch species they are blackish early on. |
| Scabers | Small, rough, scale-like tufts on the stem surface that can be rubbed off. Very young mushrooms may not have developed them yet (D. Miller, Danny’s DNA Discoveries), and Hemileccinum subglabripes has faint scabers that are easy to miss (D. Miller, PNW Pictorial Key). |
| Flesh | White and firm. Staining differs by species: some barely change, some slowly turn gray, and some stain pinkish or reddish before turning gray to blue-gray (Siegel & Schwarz; D. Miller). Blue to blue-green stains at the stem base are common in the orange-capped group. |
| Spore print | Brown, from dusky brown to dull or olive-brown depending on species. |
| Mycorrhizal | Always with trees. Host tree, flesh staining, and whether the cap margin has a band of overhanging sterile tissue are the features Mushrooms of Cascadia (Siegel & Schwarz) highlights. Host is a clue rather than a lock: DNA from PNW red-capped collections found one genetic group under hardwoods, conifers and madrone (D. Miller). |
The scabers are the giveaway
Scabers are small, raised tufts or scales against a paler stem, and they can be rubbed off. Suillus stems instead carry glandular dots that look painted on, and king boletes have a net pattern (reticulation) at the top of the stem (D. Miller, PNW Pictorial Key). Very young Leccinum may lack scabers; flesh that stains red or gray-blue helps separate them from the king bolete group.
Key PNW Species
These are the four Leccinum names most often applied in the PNW. The names are shaky. Mushrooms of Cascadia (Siegel & Schwarz) says the orange-red group is a confusing complex with no clear concepts for the available names. Danny Miller reports that DNA from over a dozen PNW red-capped collections fell into one genetic group, and says the names on local Leccinum can’t yet be trusted (D. Miller). L. aurantiacum, the European name usually given to any red-capped Leccinum, has never been found in the Pacific Northwest by DNA (D. Miller).
Birch Bolete
Leccinum scabrum group
Cap 4–12 cm, dark brown to dark gray, fading to gray or tan with age. Always with birch, often planted birch on lawns. Blackish scabers on a whitish stem. Edible with good flavor, but often quite slimy (Siegel & Schwarz). Several look-alikes exist, some staining blue at the stem base.
Edible Birch Photo: Sharon Squazzo / CC BY via iNaturalistPonderous Bolete
Leccinum ponderosum group
Cap 7–20 cm, dark red-orange to red-brown, large and rounded; stem often has blue to blue-green stains at the base. Under conifers, especially pines. Edible with caution: some people react badly to orange-capped Leccinum, so cook it well (Siegel & Schwarz).
Edible — Caution PineManzanita Bolete
Leccinum manzanitae
Dark red to reddish-brown, viscid cap with flaps of tissue at the margin when young. Grows with manzanita and madrone (Arora; Bessette). Described from California; reported from Oregon, Washington and BC (MycoMatch). Edible with the same caution as other orange-capped species.
Edible — Caution Madrone Photo: Richard Sullivan / CC BY-SA via MOAspen Bolete
Leccinum insigne
Rusty orange to reddish-brown cap, paler orange than the others (Siegel & Schwarz). Associated with aspen, and with birch according to some authors (Arora; Bessette). Reported from Washington and Idaho (MycoMatch). Edible with caution; cook it well.
Edible — Caution Aspen Photo: moorebuesing / CC0 via iNaturalistHabitat & Where to Look
All Leccinum are mycorrhizal with trees. Host trees are a useful starting clue, but the species concepts overlap, so don’t treat a host as a guarantee of the species name.
- Birch: The birch bolete group is common with planted birch on lawns and in parks (Siegel & Schwarz). L. scabrum was probably introduced with planted birches but also occurs with natural birch, for example in northern Idaho and Washington (Trudell). Brown-capped urban-birch look-alikes include L. schistophilum and L. cyaneobasileucum, which stain blue at the lower stem.
- Pines and other conifers: L. ponderosum grows under conifers, especially two-needle pines, and is common across Cascadia in late summer and fall (Siegel & Schwarz). Smith’s description records ponderosa and lodgepole pine, and the type collection came from ponderosa and sugar pine (via MycoMatch). A darker-capped species in fir-hemlock forests appears to be L. fibrillosum (Siegel & Schwarz).
- Manzanita and madrone: L. manzanitae is reported with both (Arora; Bessette). It is the most common Leccinum in California’s coastal forests (Thiers) and is reported from Oregon, Washington and BC.
- Aspen: L. insigne is associated with aspen (Arora), and Bessette also lists birch.
Season & Timing
Leccinum is mainly a fall genus in the PNW. Research-grade iNaturalist observations from Oregon and Washington are mostly from September to November:
Based on 434 research-grade iNaturalist observations from Oregon and Washington
Per Mushrooms of Cascadia, L. ponderosum fruits in late summer and fall, and birch-associated L. scabrum can fruit in summer in irrigated urban areas (Siegel & Schwarz). Within iNaturalist, L. manzanitae records cluster in October and November, while L. insigne has only 25 research-grade records in Oregon and Washington, spread from June to October. That is too few to call a season.
Scout Tree Partners with Forayz
Layer forest type data over satellite imagery to locate aspen, madrone, and pine stands across the PNW — then plan your fall forays.
Edibility & Cooking
The Leccinum species covered here are listed as edible, with a caveat for the orange- and red-capped group.
Birch bolete group: edible with good flavor, but often quite slimy (Siegel & Schwarz).
Orange-capped species (L. ponderosum, L. manzanitae, L. insigne): Mushrooms of Cascadia says some people have adverse reactions and that these should be cooked well if eaten. MycoMatch notes that orange Leccinum have been implicated in poisoning episodes, and D. Miller says some people report allergic reactions or gastrointestinal distress from the red-capped ones (D. Miller, PNW Pictorial Key).
Adverse Reactions to Orange-Capped Leccinum
Some people get sick after eating orange- or red-capped Leccinum, even when the mushrooms are cooked. Because the species are so hard to separate, assume any orange- or red-capped Leccinum could cause a reaction. Cook it thoroughly and try a small portion the first time.
Not Sure Which Bolete You Found?
Our Bolete Finder tool walks you through identification step by step — cap color, pore color, stem texture, host tree — and narrows down your find from 20+ PNW bolete species. It covers Leccinum alongside king boletes, Suillus, and the rest.
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; Danny’s DNA Discoveries and the PNW Pictorial Key (© Danny Miller); iNaturalist observations.