Observation 28233: Xerocomellus chrysenteron group

Direct side-by-side comparison of Boletus truncatus (at left) and Boletus chrysenteron (at right).

This comparison illustrates some of the non-microscopic field marks that I have been using to separate the two species.

Boletus truncatus usually has a relatively more robust stem with the red color concentrated towards the apex and descending in distinct scales, and a darker and less areolate-cracked pileus.

Boletus chrysenteron has a more slender appearance, with the red coloration more oriented towards the bottom of the stipe and with less prominent “red-scales-on-yellow background” appearance.

The spores of photo 4 are B. truncatus, and those of B. chrysenteron are in photo 3.


Copyright © 2009 Christian F. Schwarz
Copyright © 2009 Christian F. Schwarz
Copyright © 2009 Christian F. Schwarz
B. chrysenteron
Copyright © 2009 Christian F. Schwarz
B. truncatus

Proposed Names

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Eye3 = Observer’s choice
Eyes3 = Current consensus


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Agree, in the sense of Bay Area material…
By: Dimitar Bojantchev (dimitar)
2009-11-15 00:40:02 CST (-0600)

I fully agree with these findings in the sense of Bay Area material. In general, X. chrysenteron is a fairly gelatinous concept and I even doubt that we have the real deal exactly, except that they all look alike. In the Eastern NA it tends to be even smaller. My European collections are more similar to ours. In my experience X. truncatus is very common near Live Oak. The European X. porosporus has similarly truncated spores. I banged my head against that wall sometime ago, but decided that there are more profitable gigs than trying to id Xerocomus. The gazillion fruitbodies in Northern California and Oregon under various conifers that one can see right now look more like X. truncatus, but are not with truncated spores.

Nice comparison!
By: Nathan Wilson (nathan)
2009-11-15 00:18:37 CST (-0600)

Would you mind actually creating a separate observation and then reusing the images? This observation would then get assigned to one of the species (keeping the appropriate micrographs) and the other would be the other. This will clarify the voting and will make these useful observations more prominent to people looking at the corresponding description pages. Thanks!

B. truncatus and B. chrysenteron side by side.
By: Christian (Christian Schwarz)
2009-11-14 23:22:14 CST (-0600)

Created: 2009-11-14 22:18:27 CST (-0600)
Last modified: 2016-04-27 14:25:08 CDT (-0500)
Viewed: 92 times, last viewed: 2018-01-20 15:32:12 CST (-0600)
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