Observation 189369: Xerocomus subtomentosus group
When: 2014-11-23

Notes: Found by Hwy 263 about one mile before the entrance to the park. First there were three growing within 50 cm from each other, then there was one growing solo about 10 m away.

A few typical spores measured 10-14 × 4-5. A cystidium: 50 × 10.5; a 2-spored basidium: 30+4 x 10.

The habitat “near Big Basin State Park” is mentioned in the original Halling paper. Prominent yellow basal mycelium is not mentioned.

Proposed Names

55% (1)
Recognized by sight: the dry, finely velvety brown cap does not rule out A. citriniporus (but it does rule out A. flaviporus). The stature is taller and more gracile than A. citriniporus, and the pores (while still bright) are slightly duller. The prominent yellow basal mycelium is a good indicator for Xercomus subtomentosus in our area, since the Aureoboletus either have obscure or absent rhizomorphs, or white rhizomorphs. All three of these species occur regularly in our area, and I have definitely made this mistake before. Tasting the cap surface is a good way to tell – sour and acidic (kind of pleasantly lemony) in the Aureoboletus, mild in Xerocomus and Xerocomellus. Regardless, excellent documentation of this species! Mainly due to procrastination I have never got around to applying ammonia to our local material.

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Eye3 = Observer’s choice
Eyes3 = Current consensus


Add Comment
Thanks; stature; vodoo
By: Sava Krstic (sava)
2014-11-25 02:19:01 CST (-0500)

Christian and Debbie: thanks for the comments and the correct id of this bolete. Thanks also for the welcome. When we moved to California, it started to rain. (Perhaps it’s a coincindence.)

Regarding the stature: Halling says “Stipe 5-6 cm long, 1-1.5 cm wide, subclavate to equal, pinched at the base”, based on six examined collections. These are tall stipes, as in the drawing of “citrinoporus” at http://www.mykoweb.com/BH/boletes1.html (the last in the list). On the other hand, the stems in the photos at http://www.mykoweb.com/... and
http://mushroomhobby.com/... look much heavier. I’m wondering if such a range in stipe length/width ratio is OK.

Regarding chemical voodoo: if testing for iodine reactions is good, bust most of the other tests are nonsense, then where does one draw the line? In this case, a color change happens (to something redder than the original). If it is consistent and does not happen in look-alikes, then I suppose it’s a useful test.

Hey Sava!
By: Debbie Viess (amanitarita)
2014-11-24 14:05:54 CST (-0500)

Welcome to our neck of the (mushroomy) woods!

I agree that this looks more like subtomentosus rather than one of the Aureoboletus, but I disagree about that taste taste … all of the Xerocomellus taste “lemony” to me (and not just to me)! The yellowish basal mycelia is a much better character; dry cap could go either way: subtomentosus or citriniporus. As to gracile vs fat fbs … diversity happens.

You have picked a good year to join us … we actually have mushrooms in the woods, a nice change from 2 years of drought!

I agree with Dimitar that a lot of these chem tests are bunk, or as he claims, “voodoo” … one man’s red brown is another man’s dark vinaceous!

Consider joining us for a local BAMS walk at Joaquin Miller Park the Sunday after Thanksgiving. You can contact me privately for details.

Created: 2014-11-24 00:19:15 CST (-0500)
Last modified: 2014-11-24 13:10:49 CST (-0500)
Viewed: 51 times, last viewed: 2016-10-27 19:52:54 CDT (-0400)
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