Observation 141832: Boletus discolor (Quél.) Boud.
When: 2013-08-04
No herbarium specimen

Notes: A single specimen (7.5 cm tall) growing under oaks.

The cap is 5.8 cm in diameter, dingy dark yellow with brownish areas (for some reason the camera flash makes it look orangish), smooth and somewhat glabrous to touch, bruising blue when handled.

The stipe is 6.5 cm long, tapering down. It’s 2 cm wide at the apex and 1.1 cm wide near the root tip. It’s smooth/glabrous to touch. The entire stipe is colored pale yellow, with barely noticeable diffuse reddish tints; not punctate/pruinose; some brownish discoloration is visible at the base. The surface is soft enough for fingerprints to be left on handling (photo 012). The stipe doesn’t discolor when handled, but dragging a pressed nail against the surface will bruise it blue.

The tube mouths are dark orange, but the tubes themselves are yellow. The tube layer is up to 1 cm deep.

The exposed flesh is pale yellow, instantly staining blue. Eventually the color dissipates to pale grayish blue.

Ammonia = olive-brown on cap; yellow orange on context. KOH = amber brown on cap; orange on context. Both chemicals erase the blue stain of exposed flesh.


Staining of the flesh with aqueous NH4OH (left half) and 5% KOH (right half)

Proposed Names

28% (1)
Recognized by sight
28% (1)
Recognized by sight: Nice find
55% (1)
Recognized by sight

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Eye3 = Observer’s choice
Eyes3 = Current consensus


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Created: 2013-08-05 00:15:56 CDT (-0400)
Last modified: 2013-08-05 07:43:39 CDT (-0400)
Viewed: 66 times, last viewed: 2017-06-28 12:29:04 CDT (-0400)
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