Observation 27068: Boletus orovillus Thiers & Kowalski
When: 2009-10-22
No herbarium specimen

Notes:

[admin – Sat Aug 14 02:00:32 +0000 2010]: Changed location name from ‘Fortuna, Humboldt County, California, USA’ to ‘Fortuna, California, USA

Proposed Names

43% (6)
Eye3
Recognized by sight
54% (7)
Eyes3
Recognized by sight: for want of a better name. one of the yellow, bluing non-MR boletes.
32% (2)
Used references: Bessette, A., W. Roody and A. Bessette. 2000. North American Boletes: A Color Guide to the Fleshy Pored Mushrooms. Syracuse University Press, Syracuse, NY. 396p.
Both, E. E. 1993. The Boletes of North America: A Compendium. Buffalo Museum of Science, Buffalo, NY. 436p.
Smith, A. H. and H. D. Thiers. 1971. The Boletes of Michigan. Univ. of Michigan Press, Ann Arbor, Michigan. 417p.
Watling, R.and A. E. Hills  2005.  British Fungus Flora: Agarics and Boleti Vol.1. Boletes and Their Allies.  Royal Botanic Garden, Edinburgh, England.  173p. (with Flora of British Fungi Colour Identification Chart.  1969.)

Please login to propose your own names and vote on existing names.

Eye3 = Observer’s choice
Eyes3 = Current consensus

Comments

Add Comment
$50,000 for a pile of sawdust
By: Alan Rockefeller (Alan Rockefeller)
2009-12-14 19:44:10 PST (-0800)

$50,000 for a pile of sawdust sounds like a bit much for my christmas budget this year. I’ll give you $5 for a spore print though.

$50,000
By: Erin Page Blanchard (CureCat)
2009-12-14 15:28:55 PST (-0800)

Are you for real?

You are offering to sell the mushrooms for study… Apparently you have no idea how overwhelmed mycologists, both professional and amateur, really are. No one is going to buy these mushrooms from you for 50 thousand dollars.

You might be able to sell a big bag of the processed, dried boletes on e-bay for $50.
If you are looking to make a fortune, forget the mushrooms and focus on something lucrative.

Taking it Seriously
By: Timothy (greenpearfarm)
2009-12-10 09:51:00 PST (-0800)

I copied this from my 10-24 comment:

“More ‘fruiting’: When I removed the cluster of butterball boletus on Wednesday I cut through some mycellium a couple of inches from the mushrooms. Yesterday, two days later, the surface of the sawdust where the mycelium had been exposed to air and light had skinned over an area about 3in.×3in.,and yellow caps are forming another cluster. The caps measure up to 5mm. See image 62020. Images 62020 thru 62023 were photographed yesterday, 10-23-09.”

Image 61679 shows these mushrooms before removal, and 61680 thru 61683 and 61685 thru 61687 are the same cluster.

I was a little surprised when I saw these primordia ( image 62020) emerging directly from the mycelium while at the same time fusing tissue at the base into a cluster with many primordia so soon after removing the cluster three days before.

Photos 69165 and 69166, taken yesterday, are the primordia that emerged in 3 days and never grew, and one of the remaining boletes that did grow. I had previously cut off some similar boletes on the same cluster, and this can be seen. Note the red flesh. The stipe on this is bulbous, not pinched down at the base as is common in age, and is at least as thick as it is high. Cap is approximately 7 cm.

Photos69167 and 69168 were also taken yesterday

I have put this “Huge mushroom grow kit” up for auction on e-bay item number 260521300227 with the title “Sawdust Pile with Yellow Boletus Mushrooms”.
To study this boletus phenomena properly will take more resources than I have, and I want this to go to someone who is committed, and able to carry through with this project. If this e-bay auction is not successful, I will do what I can and cross that bridge when I come to it.

B. Parasiticus and Flavor
By: Timothy (greenpearfarm)
2009-12-09 17:51:56 PST (-0800)

Dave, there is another fungus involved besides the bolete that is growing in my sawdust pile, and it is impossible to tell with my eyes if the bolete is getting its nutrition by breaking down the sawdust (saprobe) or living on or in the other fungi mycelium either internally or externally (parasite). The way it is generally presented, the Buchwaldobolets are saprobes. I believe now this one at least is parasitic. The host mycelium is very fine, and so is the parasitic bolete mycelium, and there is nothing else fruiting on the sawdust but the Bb. spectabilis.

I used B. parasiticus as an example of how a boletus can be a parasite. As far as I can tell, there are no proven boletus saprobes. I have never seen a B. parasiticus in the flesh, but I suspect they may not be particularly related.

The Bb. spectabilis that I cooked were all mild flavored with slight mushroom taste, slight delicate sourness, subtle aroma, but always pleasant. Mushroom lovers learn to like strong flavored mushrooms, like shitake, but many people are turned off by strong mushroom taste and mushroom texture, and will not eat mushrooms.

For what it ‘lacks’ in strong flavor it makes up for in complementing and absorbing other flavors, an always pleasing crunchiness and meat-like texture, and golden beauty. They’re also nice to cook because they don’t exude a lot of liquid, and they brown quickly.

Spoken like a true Boletivore,
By: Dave in NE PA
2009-12-09 16:25:15 PST (-0800)

Timothy. I generally remove the tubes (on all but the yougest specimens) before cooking or dehydrating most boletes (Suillus pictus is an exception, as these tasty mushrooms don’t have easily removed tubes).

Is this species related to B. parasiticus? It’s probably the only non mycorrhizal bolete I find around here (PA). I tried eating a small sample of these once, but was not favorably impressed by the flavor.

A Choice Edible
By: Timothy (greenpearfarm)
2009-12-09 12:28:47 PST (-0800)

We have been test cooking samples of these boletes, both fresh and dried, small and large, early emerging mushrooms and mushrooms last week with mold on top (14cm). I have poached, sauteed, and made tea of fresh and dried.

These boletes have some peculiar but wonderful qualities considering most mushrooms I have eaten.

In my experience, bolete stems fill with insects quickly, and the tubes turn mushy. With this Bb. spectabilis, I have never observed an insect hole in the stems. The older caps have some tunneling, but minor. The oldest ones with the mold on the cap are rotting now.

Mushrooms generally exude liquid as they cook. These boletes give off no water in the pan when sauteed. As they cook they do exude a slightly thick yellow liquid, but only on the surface of the slices. They do not give off enough liquid to flow into the pan.

Fresh and dried, these boletes turn from yellow to brilliant yellow in the pan, and brown easily. When a slice is sauteed in a little olive oil alongside slices of garlic, and slices of onion, the bolete will be golden with brown crusty edges and crunchy tubes when the garlic is a little too browned and the onion is not yet brown. Dried and reconstituted, they have a similar appearance to fresh. See photos 62022 and 62023 for the color change in the pan when cooked in a little olive oil. These are fresh. Photo 69002 shows a dried slice after soaking in water for 16 hours, and photo 69003 after the slice was browned in a little olive oil.

Lightly cooked, the boletes have a texture somewhat like lightly cooked zucchini. There is always a pleasant crunchiness. Here the comparison with zucchini ends. These yellow boletes hold their form well no matter how long they are cooked, and as they are cooked the texture is more meat-like, but still crunchy. This is true with fresh or dry, young or old. On the very old samples of cap (poached and sauteed) the flesh still had a pleasant crunchiness, but the tubes were slimy. The tubes are good to eat until they are quite old, and are almost non-existent when young. Photo 69004 is a slice of the bolete in photo 66450, and is cooking (stem and a little bit of cap not rotted) in photo 69005.

Sauteed in olive oil and a little salt, the taste is quite mild, with a slight mushroom taste, and when pressed, people will say “maybe like butter”, or “nutty?”. It may be the browning that is tasted, or the tubes which become crispy. There is absolutely no “earth” taste, and no “woody”taste although “forest?” has been suggested as a subtle taste. “Vinegar, but good” has also been suggested as a subtle taste. Dried, their flavor is a little stronger, but these boletes are never strong tasting. These boletes blend well with other foods, and in an egg and cheese omelet they were great.

I re-hydrated some I had dried and drank the yellow tea hot.. A minute after sipping, my mouth began to water some, as though from citrus, or simply hungry. The tea was pleasant and aromatic. It was an OK tea.

The Bb. spectabilis on my sawdust pile deserves more study. For the sake of taxonomy, the mechanism at work here may be the key in figuring out what this Buchwaldoboletus is all about. Also, the many qualities of this boletus suggest it will fill a niche in the cultivated mushroom market which so far is lacking any boletus.

More
By: Timothy (greenpearfarm)
2009-12-08 17:11:38 PST (-0800)

The stump and firewood pile both had growth of Trichaptum abietinum and Dacrymyces palmatus on wood that was slightly punky. In MO observation 29814 photo 68666, D. Palmatus is on top of the stump while brackets of T. abietinum, out of focus are on the bark below. In photo 68731, D. Palmatus is growing up through T. abietinum mycelium and crust on a piece of firewood. Both seem indifferent to one another. I am sure both were in the log I sawed into the sawdust pile. The cream colored Mycelia mat that was previously the cambium layer under the bark of the tree develops sporocarp of Trichaptum abietinum. Below the white at the base of Dacrymyces palmatus, the color changed to a watery brown – not white. I think the cambium mycelia mat is Trichaptum abietinum. I have a dry sample from the firewood pile. I’m guessing that the spores for both of these wood-rotters were carried there by the same beetles that killed the tree, or later wood borers, and mycelium for both were in the tree when it was sawed.
Saprobe or parasite? What is this boletus growing on my sawdust pile? The first impression of everyone seeing this bolete, including myself, is that it is a saprobe, or wood rotting boletus.
After all, there is nothing else visible growing in or on the sawdust, except mycelium that I expected from the bolete. Therefore it must be rotting the wood for its nutrition.

As far as I can tell, the idea that any boletus is capable of gaining its nutrition from its ability to rot wood is circumstantial. Buchwaldoboletus sp. and B. orovillus are all found on rotting wood, or wood that is in the process of decay by other fungi that are known wood-rotters.

If one looks at B. spectabilis as a parasite of other fungus, Boletus parasiticus is an example of how this can be done. B. parasiticus grows from within the mycelium it parasitizes. Seems likely for B spectabilis too. But could a boletus on rotten wood or sawdust parasitize using ectomycelium, and live on nutrients in the enzyme reduced sawdust? Again, this sawdust was inoculated with T. abietinum (white rot) and D. palmatus (brown rot).

Firewood and sawdust pile revisited
By: Timothy (greenpearfarm)
2009-12-08 11:38:49 PST (-0800)

I picked through my white fir slab firewood pile today looking for evidence of more fungal growth from within the rotting wood. Most of the pile dried out during the summer, and no growth is happening. Out of the sun, there is abundant T. abietinum. Another fungus has fruited in wood previously decayed by the T. abieticum on the stump and in the wood along with T. abieticum. This fungus I have identified as Dacrymyces palmatus and is Mushroomobserver observation 29814.

What is this?
By: Timothy (greenpearfarm)
2009-12-06 21:42:13 PST (-0800)

There are two methods of classification of this bolete that are at odds with one another.
This type of bolete has been identified as genus Buchwaldoboletus (pronounced “buck…”) since 1969. There are currently three Buchwaldoboletus species listed:
Buchwaldoboletus lignicola Pilat (1969)
Buchwaldoboletus spectabilis Watling (1988)
Buchwaldoboletus sphaerocephalus Watling (2004) – (deprecates Buchwaldoboletus hemichrysus Pilat 1969.)
Alternatively, the most “correct” or “scientific” (in my opinion) seems to be to list these boletes in the genus boletus, with no distinction being made from the much more common mycorrhizal boletes. Unfortunately, the mushrooms on my sawdust pile I do not believe to have been identified using this method. There is one apparently saprobic bolete described using this system, Boletus orovillus Thiers (1966), that possibly has no synonymous Buchwaldoboletus species.

The subject mushroom is a yellow boletus growing on a softwood sawdust pile that has been inoculated with Trichaptum abietinum, a common pioneer wood-rotting (white pocket-rot) polypore. There are no trees or shrubs nearby, and therefore little possibility of mycorrhizal association. The stipe and cap shape and size are quite variable, especially in light of the polymorphism I described as form 1 and form 2 in previous comments. (See photos 68316 and 68317 of the second form 2 mushroom. I have not yet picked it for good identification).

There are several features of the subject bolete that seemingly set it apart from the other buchwaldoboletus that grow on rotten stumps, chips, or sawdust :

Pileus size – at 150 mm is half again as large as the other buchwaldoboletus species.

Pileus thickness – the subject bolete seems to have an especially thick pileus, noticeable in early stage of growth.

Basal mycelium – the stipe base of the subject bolete is red and the rhizomorphs that sometimes extend several inches into the substrate are reddish brown to dark brown. Mycelium is very fine, hairlike, and silver. Yellow basal mycelium is typical for buchwaldoboletes but not the subject bolete.

Pore color – for the subject bolete ranges from very light yellow, to bright yellow, to brown and dark brown. The pores are not red or orange.

I have decided the subject yellow bolete is most likely a Buchwaldoboletus spectabilis (Watlin 1988). I will refer to it as such.

Saprobe, parasite, or both? Many studies of Boletus suggest that it could be one or the other or both to different degrees.

Because the B.b. spectabilis emerged at the same time as the sawdust pile was being rapidly colonized by the Trichaptum abietinum it seems likely that B.b. spectabilis is a parasite, and T. abieticum is the host.

It’s more complicated, but it makes more sense
By: Timothy (greenpearfarm)
2009-12-02 19:27:50 PST (-0800)

In an earlier comment (observation 27068) I described how the log, bark and all, is mounted on a carriage and sawn by a 5 ft circle saw with a 3/8in thickness.

In one of my first comments (observation 27068) I mentioned the fir had been standing dead for a couple of years before I cut it down and milled it. I mentioned the beetle(?) larvae holes throughout the tree with live larvae – I know because I looked closely after laughing at juncos and white crowned sparrows feeding on the freshly sawn slabs.

The top of the tree was rotten and had broken out the previous winter.

The bark was still fairly well attached to the log, but after the slab was cut off the side of the log, sometimes the bark would come loose, and between the two was a sheet of fungus mycelium that was previously the cambium layer under the bark. It had the consistency of thin rolled pie dough, smooth, soft and cold as it draped over my hands. I put it out of my mind as it had nothing to do with milling lumber.

The slabs that are cut off the outside of the log I cut into firewood. Some of the slabs toward the top of the tree are rotten or punky, and I am burning this now.

Last night as I was adding this wood to the fire, I noticed a knot, from a limb I had cut flush with the bark, had been overgrown by fungi. This firewood (Abies Grandis, Grand Fir we call White Fir) has an abundance of one kind of crust fungi, and I now believe these to be the fruiting bodies of the cambium mycelium I noticed as I was sawing the log 8 months ago. Other photos show the fungi growing from punky wood, and mature shelves on and from the fir stump.

Generally, each cut passed through a substantial amount of this sheet of mycelium, and the particles were thoroughly mixed into the sawdust pile. After examining the pile closely this afternoon, I found two small areas (2 sq. in.) where this polypore was beginning to grow on a vertical surface.

My guess is Stereum Sanguinolentum, but there are approximately 392 species in this genus, and I may not even have the right genus.

Is this yellow bolete not saprobic at all, but parasitic on the mycelium of this polypore? Intuitively, this makes sense to me. This is from a description of Buchwaldoboletus Lignicola…

“Habitat: found on stumps or trunks of conifers. Exceptionally found on sawdust, but association will always remain with conifer wood. Often growing on wood decayed by Phaeolus schweinitzii and possibly parasitic on its mycelium.”

I have submitted photos of this saprobic polypore to Mushroomobserver.org. Observation
No. 29363.

Update 11-27-09
By: Timothy (greenpearfarm)
2009-11-27 16:14:24 PST (-0800)

It has now been 1 ½ months since I first noticed these boletes on the sawdust pile. I would guess that they had been there for a week before that. In the mean time, more caps keep emerging.

We have had some recent hard rains, and the temperature inside the pile is now 52deg. F.

There is no vegetation or other mushrooms on the pile except for the boletes. Some of the mushrooms on the right in photo 61678 are shown in photo 66450 taken last Monday. I have removed one mushroom from this cluster, and part of another. The cap that is cut has a few maggots, and the stipe none. Maggots are not a big problem. There are spots of blue/black mold on these almost 2 month old caps, but it is easily peeled off with the cap cuticle.

The stipe cuticle reddens towards the base with age, and so does the stipe flesh at the very base, and solid mass that the stipe fruits from. The color is red with an orange cast, darkening to red brown to dark brown with age and depth. The mycelium is very fine, and never yellow.

Blue stain when bruised is erratic.

The pores are very fine when young and light to bright yellow. They are irregular polygonal. In age they darken to yellow, yellow/green, yellow/brown and then dark brown. The tubes are olive color. The pores are never red or reddish. The caps are spherical and incurved over the pores when young, and the cap cuticle hangs down below as a narrow fringe.

A second Form 2 mushroom has emerged. The manner in which this happens seems to be as follows:

Form 1. In all cases, this mushroom fruits initially as a cluster. Multiple primordia begin to grow from the mycelial mass, on top of, and around the perimeter of the mass. The perimeter primordia grow laterally and upwards away from the mass. Because a sawdust pile (and a rotten log) have sloped sides where they have reached their angle of repose, the primordia, at least on one side of the mass, breaks through to the surface. Now, all of the growth is directed to these mushrooms, and the other primordia on the mycelia mass wither and die. On these mushrooms, the cap us uniform and the smooth. These clustered Form 1 mushrooms have a stipe that is bulbous when young, or equal, sometimes spindle shape or pinched off at the base when old. With both young and old, the thickest part of the stipe is only slightly smaller than the height.

The Form 2 mushroom also fruits initially as a cluster. Again, the primordia begin to grow from the mycelia mass, on top of, and around the perimeter of the mass. The perimeter primordia grow laterally and upwards away from the mass.

Both of the Form 2 mushrooms that have emerged were growing near the top of the sawdust pile in shallow depressions. The perimeter primordia pushed out from 20mm to 80mm and did not reach light. These primordia eventually died.

At this point, this mushroom changes its strategy. The primordia on the center of the mycilia fuse their stipes and caps into a single mushroom. This mushroom grows rapidly in height, the stipe may have vertical ribs (originally multiple stipes), the cap is irregular shaped, and there are furrows and pits on the top. The stipe is more than twice as tall as its thickest part, and tapers evenly from small at the base to large at the top. See photos 63716 and 63718 for the original Form 2.

Sawdust details
By: Timothy (greenpearfarm)
2009-11-13 13:02:42 PST (-0800)

In previous comments I have described the size, age, and wood species of my sawdust pile. Now more details:
The bulk of the sawdust pile is the product of sawing the outside slabs off the log, bark still attached, with a 60in. circle saw that has a 3/8in thickness, i.e. there is more than an inch of log turned to sawdust in three cuts. The saw is stationary, and the log rides on a carriage, so that all of the sawdust accumulates under the blade. Plentiful spring water is used to cool and lubricate the saw, so the sawdust is wet.

After squaring up a couple of 20 ft logs, the sawdust is shoveled onto the sawdust pile with a scoop shovel (less than 1cu.ft.).

The last logs I cut were two 2ft.dia. redwood logs, and when finished, I shoveled the sawdust onto the pile, Therefore the top layer of sawdust on the pile is primarily redwood, with maybe a small amount of grand fir from the cuts before that mixed. The mushrooms seem to be growing out of this 2 to 5 inch layer of redwood sawdust, in the top layer of redwood sawdust.

This is not a high production sawmill, and the carriage feed that moves the log through the saw is always slow. I do not have to tend to it and can do other chores while it is cutting. Therefore, the sawdust particles are fine, mostly less than 2mm. This is smaller than chainsaw sawdust. However, chips and slivers of wood, knots, and bark are mixed into the sawdust. With redwood, some of the bark shreds into a red wool.

When I have examined the threads of mycelium with a magnifying glass, they were very similar in size and shape to the fibers of redwood bark they disappeared into. The mycelium is always very fine, and never yellow. The redwood fibers may be important in the ecology of this mushroom. Also, some of the clusters had larger pieces of bark or wood that the mycelium formed around and fruited.

Approximately 10% of the sawdust pile is the product of re-sawing the squared-up logs with a 1in. wide by 1/16in thick bandsaw. This saw is also stationary, and is 3ft. From the circular saw. Again, the log rides on the carriage, so that all of the sawdust accumulates under the blade. Plentiful spring water is used to cool and lubricate the saw, so the sawdust under the saw is a slurry. The feed rate for this saw is even slower than the circle saw, so the sawdust particle size is very fine, less than 0.3mm. This is shoveled onto the same sawdust pile, but not mixed in, so there are lumps of this very fine redwood and fir sawdust here and there in the pile. Some mushrooms fruit near these concentrations, but the mycelium does not seem to enter. When a cluster is “uprooted”, the mycelium threads tend to hang onto and suspend the larger particles of sawdust from the circle saw, and these appear to be substantially redwood. See photos 64624 and 64625.

Two mushroom forms
By: Timothy (greenpearfarm)
2009-11-07 09:09:29 PST (-0800)

Photo 63712 taken 4 days ago showing five form 1 clusters and one form 2 mushrump.

The observation below is laced with speculative opinions…so be it.

This mushroom has two distinct forms depending how it emerges from the mycelium.

Form 1: What I have observed up to now, the mycelium, near the surface, has organized the fruits into clusters of multiple mushrooms (sometimes a single mushroom) with the stipe growing rapidly until reaching the light, and then slowing the stipe growth, resulting in a bulbous base stipe. Photo 63713 is a recently emerged form 1 cluster. The cap continues to grow. The stipe continues to grow in girth, but not much in height except at the base, where at maturity it narrows resulting in a spindle shape stipe. Crowding in the cluster causes the “bulb” midway up the stipe to grow into a “knob” on the side of the stipe. Photos 63714 and 63715 show a mature form 1 cluster prior to removing the lower right mushroom for study. Pileus diameter 17.5cm, stipe base 2cm, midway 4.7cm, top 4.2 cm. Stipe height 5cm. Photo 63716 shows form 1 and form 2 sliced for drying.

Form 2: This fruit formed deeper under the surface. The mycelium began forming clustered primordia as with form 1, but as the pileus formed it grew over the several primordia as single cap. The primordial stipes then organized into a single stalk, which grew rapidly until pushing through the surface as mushrump. The form 2 cap is distinctly different from form 1. The margin is creased with ‘valleys’ that make the cap somewhat starlike when viewed from above. On the top of the cap, there are furrows…an unevenness that I interpret as a result of the cap initially growing over several primordia. This may also explain the cap ‘valleys’ in the mature mushroom. Photos 63717 and 63718 are form 2.. Pileus diameter 16cm. Stipe base 4cm, top 5.4cm, stipe height 10cm.

Coming…more observations on edibility, and the identification of this mushroom.

Innoculation?
By: Timothy (greenpearfarm)
2009-10-29 09:28:48 PDT (-0700)

Not by my hand. Apparently spores made their way to this sawdust pile from a far away land where the mushrooms grow (are grown?)on a sawdust pile. I have seen many sawdust piles too, but I’ve never seen anything take to redwood and fir sawdust like these mushrooms. Beautiful yellow/gold orbs emerging from fresh sawdust…what a gift.

Did These come up on there Own?
By: Eddee (eddeeee)
2009-10-28 17:24:57 PDT (-0700)

OR is this an inoculation ?, This would be a good crop of mushrooms to comically grow apparently they are edible. I have found something similar in logging area where there are sawdust mounds in WV but I think these are mostly hard woods.

New Arrival!
By: Timothy (greenpearfarm)
2009-10-28 17:02:57 PDT (-0700)

More than one week has passed since the butterball bolete has emerged from my redwood and fir sawdust pile. Any mushroom emerging from fresh (top layer) sawdust is surprising in my experience…especially redwood sawdust.

There is a furnace of decomposing sawdust below these mushrooms.

These are excellent edible mushrooms, and there were no maggots in the first we ate. This is not surprising as it is unlikely there be much life in fresh sawdust. The older mushrooms I have not yet prepared for eating.

A new arrival! Last Sunday, October 25, a fully developed butterball emerged as a mushrump near the top of the sawdust pile. This is less than a meter from where the original butterballs made their appearance more than a week ago, on the same sawdust pile.

Image 62623 thru 62628 were taken October 26.

This mushroom has two distinct forms depending how it emerges from the mycelium.

Form 1: What I have observed up to now, the mycelium, near the surface, has organized the fruits into clumps of multiple mushrooms with the stipe growing rapidly until reaching the light, and then slowing the stipe growth, resulting in a bulbous base to the stipe. What results is image 62627, with uniformly round caps, incurved over the gills, growing as a clump.

Form 2: This newest fruit was formed deeper under the surface. The mycelium organized into a single stalk, and grew rapidly with an even stipe (see image 62626) 4 cm x 8 cm. The cap of this mushrump (12cm) was distinctly different from form 1. The margin is creased with ‘valleys’ that make the cap starlike when view from above. The margin is irregular. On the top of the cap, there were some fairly broad (1cm) deep (3mm) irregular furrows. Cap dry, yellow/tan, stipe yellow changing to yellow tan with slight irregular grey patches.

nice documentation of the heat generated by these saprobic boletes.
By: Debbie Viess (amanitarita)
2009-10-27 11:12:33 PDT (-0700)

I have noticed the substrate warmth myself, but never bothered to document it with a thermometer!
B. orovillus has been our catch-all term for these yellow woodrotters. We need to examine them more closely, especially under a scope, to see where they actually fall out. We have had these discussions before on this site over other yellow saprobic boletus in California.

You are the first person that I know of who has eaten this mushroom. And you are correct, as a saprobe it would be a likely candidate for cultivation. You go, guy! California’s first bolete farm!

A couple of other yellow Non MR Boletes
By: Ron Pastorino (Ronpast)
2009-10-24 15:41:43 PDT (-0700)
are out there. One is called Boletus sphaerocophalus and is described in the Bessette Bolete book. It matches many of your specimens’ characteristics but more work would be needed to confirm. Also, some people now want to call all these non-mycorrhizal boletes “Buchwaldobolete”. Hopefully, somebody will be willing to some molecular studies on this small but interesting group.
More observations
By: Timothy (greenpearfarm)
2009-10-24 14:29:12 PDT (-0700)

It appears that all non mycorrhizal yellow boletus are considered to be of the species B.orovillus. There are many obvious differences in the ‘variations’ of B. orovillus and it will be interesting to see how the scientific names work out as the species are finally differentiated. In the meantime, I am giving this mushroom the common name “Butterball Bolete” because it is descriptive, and has potential consumer appeal as a commercial mushroom.
On Wednesday, October 21, I removed the center one of the three clusters shown in image 61678, and took it to the Humboldt Bay Mycological Society meeting. Last night I cleaned off the sawdust, removed the tubes, and trimmed the butterball bolete. As it cooked it turned to a bright golden color, and the aroma was subtle but pleasant. Cooked, these boletes are very much like the edulis, except for the yellow color. They are not inferior, and seem better than the edulis, but maybe that just the color. No stomach upset, and we ate homemade pesto on pasta an hour after eating the butterball boletes.

Additional observations:

I have had a sawdust piles at this location for the past 30 years, and on several occasions, when the pile became too large, I have moved it back under the redwoods to decompose with the leaf mold. For the past year I have been planning to move the sawdust pile as before because it was a little larger than ever before, but never got around to it yet.

The mass of the butterball’s mycelium are definitely growing in fresh (sawn 6 months ago) 2nd growth redwood sawdust, mixed and layered in the pile with grand fir sawdust about 50/50. The fir that I cut had been standing dead 2 to 5 years, and the log was full of small grubs (1/8 in.) with holes spaced throughout the wood from 2" to 8" apart or so. The fresh layer of sawdust is on top of other older layers of redwood and some douglasfir sawdust from logs and lumber I cut a few times over the last 5 years, since the previous pile was removed.

A number of times in years past, in the summer, I have thrust my hand down into the center of the pile to see if the decomposition was making the interior so hot as to be a fire danger. It was always noticeably warm but not hot.

Yesterday I inserted a thermometer toward the center of the pile, near the mushrooms. 81 deg. F. Air temperature 62deg. F. The mycelium reaches down to the vicinity of this warmth, and the warm moist air is emerging from beneath the mushrooms. This also may explain why the rust brown spore coloration was found on top of the cap and not beneath the cap.

More ‘fruiting’: When I removed the cluster of butterball boletus on Wednesday I cut through some mycellium a couple of inches from the mushrooms. Yesterday, two days later, the surface of the sawdust where the mycelium had been exposed to air and light had skinned over an area about 3in.×3in.,and yellow caps are forming another cluster. The caps measure up to 5mm. See image 62020.

Images 62020 thru 62023 were photographed yesterday, 10-23-09.

Stipe color: The stipe cuticle is yellow, but as it ages, the bottom 2/3 changes to reddish, red brown, and then where it joined with the cluster is dark brown. This can be seen in image 62021. The upper 1/3 remains yellow.

Boletus ? different than B. orovillus
By: Timothy (greenpearfarm)
2009-10-23 10:56:05 PDT (-0700)

pileus: B. Orovillus has a surface sticky when moist, B.? not sticky when moist…feels like pie dough. B.? has no fibrils, but is glabrous with faint cracks (aerolate?). The cap is up to 3.5cm thick. Bluing: when I first found these on 10/16/09 the largest cap was 6 cm dia. The pores and flesh turned a faint bluish when scraped or cut. A few days later, the flesh turned a dark inky blue when cut, especially near the base of the stipe, the pores bluing less. It has been a week now, and the largest cap is 9cm dia., and the flesh stains very little and erratically. In all cases, the staining fades within a few hours back to bright yellow, except the pores, where bruises are brown, red brown, or slightly bluish.

Hymenophore: The pores on the question Boletus are smaller than on the B.orovillus, by appearance in the photos. The largest pores are 2 or 3 per mm.

Stipe: 4.5cm long, 4.5cm broad, bulbous. Most of B. ? fruit in dense clusters. The mycelium looks like small, shiny silver animal hairs in the sawdust.

I have not been able to elicit a spore print, but staining on the caps suggests brown or red brown but I could be wrong.

For appearance I would suggest B. appendiculatus except that it is growing in clumps (and solitary) on fir and redwood sawdust.

Created: 2009-10-22 22:22:03 PDT (-0700)
Last modified: 2012-10-22 16:11:27 PDT (-0700)
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