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It seems early in the season to have such an explosion of fungi growing on the property this year.  The rains started early in October, and the soils have never completely dried out.  This has fostered the growth of an assortment of species of fungi that makes it look more like January here than November!  As such, it’s been very difficult narrowing down which species to feature on Mushroom Monday.  I’m not sure we’ll have enough Mondays this season to feature them all!

Boletus truncatus is just one of many early season fungi growing here this season (click any image to enlarge)

This species though is worthy of posting.  Until late last season I’d never seen a member of the Bolete genus growing here.  Probably because I wasn’t looking early enough after the start of the rainy season.  The only specimen I found last year was significantly decayed, and hardly worthy of a photograph.

This year though I’ve been watching for them, and have now been rewarded with finding a number of Boletus truncatus (also once known as Xerocomus truncatus) scattered along our east-facing slopes, growing in mixed woodland under Douglas Fir, Bay Laurel, and Redwood.

Unlike most of the other species highlighted in our Mushroom Monday posts thus far, the most notable feature of Boletes is that although these mushrooms have stems, they lack gills underneath their caps.  Instead, turning Boletes upside down reveals a unique, very sponge-like, pore structure.

Boletes have pores beneath their caps, not gills. With this species the pores may turn blue when crushed.

Boletus truncatus is widely distributed throughout North America, and fruits between July-November.  These specimens began to appear around mid-November this year.

The pileus (cap) of Boletus truncatus is broad, and convex, becoming more plane with age, and grows between 3-12  cm in diameter.  The surface is very dry, not sticky at all, and develops prominent cracks on the surface of the cap during development.

The cap surface of Boletus truncatus becomes cracked as it matures

The fleshy tissue of the cap of Boletus truncatus is yellow to olive-yellow in color, and the pores tend to turn a dark blue when crushed.  Individual pores are irregular in shape, approximately 0.5-2 mm in width, and the pore tubes between 7-16 mm long. [1]

The pores of this Bolete are irregular in shape around their margin

The spore print of B. truncatus is apparently olive-brown, but I didn’t attempt a spore print with these specimens.

Boletus truncatus

The stipe (stem) grows 5-10 cm long, and up to 2 cm in width.  The color is reddish, and somewhat striate along its length, becoming more yellow at the apex.

The stipe (stem) is mostly red in color, and slightly striate

At the base a yellowish mycelium is clearly visible where the stem meets the soil.

A fluffy yellowish mycelium is present at the base where the stem meets the soil

I’m not completely confident in the absolute identity of this species, as Boletus truncatus may be impossible to distinguish, even for the experts, from its cousin Boletus chrysenteron.  At least without a microscope.

This younger specimen showed a little more pink coloration just under the cap surface than the others

It’s possible these specimens could be either species.  However, it is generally accepted that Boletus chrysenteron is more likely to develop pink coloration between the cracks than B. truncatus.  As such, macroscopically most of these specimens appeared to resemble the description of Boletus truncatus more closely, but any of these pictured here could prove to be either species. [2,3,4]

This specimen exhibited no pinking in the cracks of the cap, not even toward the cap margin

Although we don’t eat the fungi we find here, Boletus truncatus and Boletus chrysenteron are both considered to be edible, although Boletus truncatus is reported to be more favored, and somewhat better in flavor, but neither is considered to be a great culinary find, and may in fact be mushy and bitter.  We’ll leave these for the slugs and deer to dine on.

Something clearly had been nibbling on this Bolete

That said though, it’s clear that some of our woodland creatures are willing to eat them.  In fact, it’s been a challenge this fall to find fungi on the farm before the slugs and squirrels do!

Almost three quarters of this specimen had been consumed, revealing some of the pore structure

The Boletes are definitely quite distinctive compared to the Agaric species of fungi growing here.  Next time you’re on a hike, and see a mushroom growing in the woods, look closely under the cap, you might be surprised what you find underneath!

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[1] Alan Bessette, William C. Roody, Arleen Rainis Bessette.  2000.  North American Boletes: A Color Guide to the Fleshy Pored Mushrooms.  Syracuse University Press.  p. 168.

[2] Boletus truncatus at Mykoweb.com

[3] Boletus chrysenteron at Mykoweb.com

[4] Boletus chrysenteron at MushroomExpert.com