Admirable Bolete Aureoboletus mirabilis — the log-loving bolete of the PNW
The admirable bolete is easy to pick out: a dark maroon-brown cap with a rough, suede-like surface, often speckled paler with age, on a long club-shaped stem, usually growing out of a rotting hemlock log. It’s a common fall find west of the Cascades and a good edible.
Most boletes come up from the ground. The admirable bolete usually fruits from well-decayed, moss-covered conifer logs and stumps, mainly western hemlock, though now and then it appears on the ground under hemlock.
Find Hemlock Habitat on Forayz
Use ecoregion layers and public land boundaries to scout western hemlock forests. Free with a Forayz account.
Identification
The rough, velvety dark cap and growth from rotting wood are the two most immediate clues.
| Feature | Description |
|---|---|
| Cap | Usually 4–15 cm across (occasionally over 20), domed then broadly convex. Maroon to dark reddish or plain brown, often paler at the edge and increasingly flecked with pale pink or whitish spots. The surface feels rough and plush, like suede, with short stiff hairs. |
| Pores | Small to medium, round to irregular; pale to greenish yellow at first, dull olive-yellow later; they do not stain blue |
| Stem | Long (7–20 cm or more) and club-shaped, swelling to as much as 7 cm at the base. Colored like the cap, streaked and spotted with pale pinkish buff. A faint net pattern near the top; the base is often sticky |
| Flesh | Whitish to pale yellow, sometimes wine-stained with age; thin and soft in the cap, which is mostly tubes, but firm and fibrous in the stem |
| Taste | Often lemony (Siegel & Schwarz, Mushrooms of Cascadia); others call it mild or pleasant |
| Spore Print | Olive-brown |
| Substrate | Well-decayed, moss-covered conifer logs and stumps, mainly hemlock; occasionally on the ground nearby |
The Log Test
Most boletes grow from the ground. The admirable bolete usually grows from rotting logs and stumps. A dark bolete with a rough, velvety cap on or next to a mossy hemlock log is very likely Aureoboletus mirabilis. The velvety cap matters: the deep purple bolete (Xerocomellus atropurpureus) can also grow on rotten wood (see Similar Species).
Habitat & Where to Look
The admirable bolete’s habitat requirements are specific and predictable, which makes it a reliable target species once you learn the pattern.
- Western hemlock (Tsuga heterophylla): The primary association. Look for well-decayed hemlock logs and stumps — the kind that are soft, crumbling, and covered in thick moss. Learn to identify western hemlock by its small cones (the size of a quarter) scattered on the forest floor.
- Mossy forests with plenty of rotting logs: Look where there are big, well-decayed, moss-covered logs and stumps.
- West of the Cascades: Common and often plentiful in western Washington, Oregon, and British Columbia, from coastal forests into the Cascades; occasional on the east slope.
The Chroogomphus Connection
The woolly pine spike (Chroogomphus tomentosus) often grows near admirable boletes and is likely a parasite of it (Siegel & Schwarz). Despite the name, it is usually found where hemlock grows and pines are absent (Trudell). If you spot dull orange, woolly-capped gilled mushrooms with widely spaced, down-running gills near hemlock logs, look around carefully — an admirable bolete may be nearby.
Season & Timing
The admirable bolete is a fall mushroom in the Pacific Northwest, with a well-defined season driven by fall rains and cooling temperatures.
Based on community observations from Oregon and Washington
Peak fruiting is in October, with strong shoulder months in September and November. A few appear in July and August, and the season tapers off through late November, with stragglers into December.
The trigger is fall rain: watch for the first soaking rains and check your hemlock logs in the weeks after.
Time Your Hunt with Soil Data
Forayz shows rainfall, soil moisture, and soil temperature — the conditions that trigger admirable bolete fruiting. Free with a Forayz account.
Edibility & Cooking
The admirable bolete is a good edible (Thiers calls it choice), and some specimens have a distinct lemony flavor. A few practical notes:
- Cap vs. stem: The cap is mostly tubes and can become waterlogged and mushy in older specimens. The stem stays firm and solid — don’t discard it. In wet weather, the stem is often the better part.
- Best young: Harvest while the cap is still firm and the pores are pale yellow. Once the pores turn dark olive and the cap softens, quality drops fast.
- Simple preparation: Slice and sauté in butter.
- Skip moldy ones: A mold (Hypomyces) often attacks this bolete, covering it in white and then yellow. Don’t eat affected specimens (Arora).
- Bug check: Like all boletes, slice lengthwise and check for insect larvae. Older specimens growing on wet logs are especially prone to bugs.
Similar Species
The velvety dark cap and growth from wood make it hard to confuse with most species. A few are worth knowing:
- Boletus fibrillosus (fib king): Its dark brown to yellow-brown cap is covered in flattened fibers rather than stiff plush hairs, its young pores are white rather than yellow, and it grows from the ground under conifers.
- Deep purple bolete (Xerocomellus atropurpureus): Dark wine-purple to reddish-brown cap that is smooth, bumpy, or faintly bloomed rather than velvety, and a red or red-dotted stem over yellow. It grows from duff, soil, and well-decayed wood, so substrate alone won’t separate it.
- Other dark-capped boletes: Several Xerocomellus species have dark caps, but none combines the rough, velvety cap with the long, club-shaped, pale-streaked stem. Check the cap texture first.
Not sure what you’ve found? The Bolete Finder tool walks through cap color, pore characteristics, staining reactions, and stem texture to narrow down PNW boletes step by step.
Taxonomy Note
Older field guides call it Boletus mirabilis, and it has also been placed in Boletellus and Xerocomus. Molecular work supports the current name, Aureoboletus mirabilis (Halling 2015; Kuo 2020), though it sits just outside the rest of that genus, and its velvety cap is unlike the sticky caps of other Aureoboletus, so a genus of its own is possible. The species is the same whichever name is used.
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.