Observation 82451: Suillus granulatus (L.) Roussel
When: 2011-11-13
No herbarium specimen

Notes: A single specimen growing under P. rigida. Looks like no veil or annulus. Whitish stipe with red-brown glandular dots on the upper half. The context staining pinkish-brown upon exposure to air within a minute.


Staining of the context upon exposure to air
Staining of the context with aqueous ammonia (left half) and 3% KOH (right half)
Staining of the pore surface with aqueous ammonia (left half) and 3% KOH (right half)
Staining of the pileipellis with aqueous ammonia (left half) and 3% KOH (right half)

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Recognized by sight
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a bit more on granulatus hosts and geography
By: Tom Bruns (pogon)
2011-11-15 03:44:43 GMT (+0000)

Walt’s observation with the hemlock is very convincing, especially since it is the Eastern North American granulatus that he is talking about, and because he obviously was paying close attention to host. But the broader literature on the species should be viewed with caution, particularly when one is outside of Eastern NA. I think what Kuo is referring to is the ITS sequence evidence that our granulatus and the European granulatus (a hard pine associate) are not the same thing. But is there any credible evidence of it ever associating with hard pines in Eastern NA?

Returning to this specimen – this sure looks like what I’d call granulatus.

By: I. G. Safonov (IGSafonov)
2011-11-15 01:51:58 GMT (+0000)

you convinced me this time! :-)

I agree that macrochemical tests can occasionally be unreliable, especially due to environmental factors and in older specimens (indeed, who can forget that epic discussion initiated by Noah’s claims!). The same goes for the context discoloration — who knows what kind of biochemical processes are taking place as fruitbodies mature under various weather conditions. Also, to quote Michael Kuo: “In fact, specimens of Suillus granulatus collected under different hosts were revealed to be genetically distinct!” This may also account for some variability between reported and observed macrochemical tests and natural tissue staining…

By: walt sturgeon (Mycowalt)
2011-11-15 00:53:16 GMT (+0000)

Other than the staining and chemical reactions, this sure looks like Suillus granulatus to me. It may be a situation similar to the Boletus edulis complex staining on the flesh that Noah has pointed out on this site. Suillus granulatus is one of the most common Suillus species in E. North America and it may be that it has variable staining reactions and that these may have been overlooked. As for tree associations, world wide it has many. In the NE,Lake States, and Ontario I see it mostly with white pine and hemlock but expect it occurs with other conifers as well. Close to home I see it commonly in woods composed of broadleaf trees and Eastern Hemlock. There are no white pines and have not been in the 35 years I have been collecting there.

Tom and Walter —
By: I. G. Safonov (IGSafonov)
2011-11-15 00:26:20 GMT (+0000)

thank you both for your comments.

I’ll refrain from making statements on the nature of mycorrhizal associations of S. granulatus due to lack of personal experience in collecting the species; however, may it be known for the record that such popular reference as Bessette-Roody-Bessette and MushroomExpert.com state that P. strobus cannot claim exclusivity for forming mycorrhiza with S. granulatus.

I spent quite a bit of time trying to match this specimen with descriptions of ringless & veilless suillus species from B-R-B, and each time S. granulatus kept coming back like a boomerang [mostly because of the stipal color/ornamentation and the extended growing season (till November)], though, admittedly, by and large this effort proved to be an excercise in futility — a recurrent story with late-blooming Pine Barrens suilluses. Other than that, I don’t think S. granulatus is a good match, particularly from the standpoint of macrochemical tests and the peculiar discoloration of the context due to air oxidation — something that S. granulatus doesn’t produce. S. granulatus or not, I think this specimen is just too old to be satisfactorily identifed…

I’m skeptical of other associations
By: Tom Bruns (pogon)
2011-11-14 21:39:11 GMT (+0000)

S. granulatus is a species I collected a lot in Minnesota and Michigan, and I never found it anywhere there was not white pine within a root’s length. It might be “under” other hosts, but I have personally never seen it without a white pine nearby.

Suillus granulatus
By: walt sturgeon (Mycowalt)
2011-11-14 21:23:13 GMT (+0000)

is mycorrhizal with various conifers including Eastern Hemlock.

it looks like the Eastern NA S. granulatus
By: Tom Bruns (pogon)
2011-11-14 20:21:36 GMT (+0000)

But that species is only found with white pine.

P. strobus might have been around
By: I. G. Safonov (IGSafonov)
2011-11-14 02:40:27 GMT (+0000)

The mushroom was brought in by a NJMA foray participant, so I don’t know about the exact habitat. White pines are very rare in the Pine Barrens, but I have occasionally seen plantations near park offices and picnic areas. What did you have in mind as to the identity of this Suillus?

could there have been an eastern white pine in the area?
By: Tom Bruns (pogon)
2011-11-14 02:34:14 GMT (+0000)

Created: 2011-11-14 02:29:21 GMT (+0000)
Last modified: 2011-11-15 04:44:04 GMT (+0000)
Viewed: 104 times, last viewed: 2016-10-26 20:26:18 BST (+0100)
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