When: 2007-11-04

Collection location: Santa Clara Co., California, USA [Click for map]

Who: Charley Pow (charley280)

No specimen available

Many mushrooms growing under a coast live oak tree. Boletus amygdalinus?


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= Observer’s choice
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amygdalinus vs erythropus (=luridiformis)
By: Roy Halling (royh)
2008-12-16 14:00:42 CST (-0600)

As near as I can remember, amygdalinus is associated with madrone and/or manzanita on the Calif coast and in the Sierra Nevada foothills, but I am sure others have more recent observations on associations. Erythropus, according to what H.D. Thiers told me, was a much rarer fungus (even at Mendocino) and grew under tan oak or perhaps oak. Both of these have Non-Reticulate stipes.

This group needs clarification
By: Administrator (admin)
2007-11-08 23:02:45 CST (-0600)

The smooth stemmed, red-pored, reddish boletes without an enlarged base are a bit challenging. Technically amygdalinus refers to the almond shaped spores. As far as field id goes, I use B. amygdalinus for the large, yellower entity that occurs in southern California. Interestingly this species is regularly eaten in southern California with no negative effects. In northern California it’s a different story. There have been several reports of mushrooms matching this general description causing people to throw up. Personally, I have never been able to see any clear difference between the ones I’ve found in northern California and I’ve always referred to them as B. erythropus. Compared to the southern California ones, they are smaller, redder and stain a darker blue. Both of them stain very quickly and intensely. I’ve never looked at the spores of any of them. It would certainly be interesting to get some micrographs of the spores of these mushrooms and try to clarify these questions.

How to tell the difference?
By: Douglas Smith (douglas)
2007-11-08 13:11:09 CST (-0600)

I’ve gone through Thiers’ desc. of both a few times now, and I still can’t see what is the difference. How do you tell the difference between B. amygdalinus and B. erythropus? (I believe this is the third time I have asked this question this week, each time in a different forum…)

More likely B. erythropus
By: Nathan Wilson (nathan)
2007-11-07 11:18:18 CST (-0600)

However without seeing the underside it’s hard to tell for sure.