|Major Groups > Boletes > Boletus > Boletus rubellus|
by Michael Kuo
Definitely not the easiest bolete to identify! Boletus rubellus has several close relatives that are virtually identical. Key features separating it from its cousins include the stem's frequently tapered base, the woodland habitat, the size of the pores (1-2 per mm), and the way the flesh changes to olive with iron salts. See the "Campellus Calculator" in the right-hand column for help separating this species from its closest look-alike, Boletus campestris.
Ecology: Mycorrhizal with hardwoods (especially oak and beech); growing alone or gregariously in woods; summer and fall; widely distributed east of the Rocky Mountains.
Cap: 2-8 cm; convex, becoming broadly convex or nearly flat in age; dry; smooth or finely velvety; margin even; dark red to red-brown, becoming brick red; becoming finely cracked in maturity.
Pore Surface: Yellow, becoming greenish yellow; bruising blue to bluish green; 1-2 angular pores per mm; tubes to 10 mm deep.
Stem: 3-8 cm long; .5-1.5 cm thick; tapered downward or nearly equal, often with a narrow base; yellow at apex, reddish below; darkening on handling; not reticulate.
Flesh: Yellow; staining slowly blue to bluish green on exposure; reddish orange in the base of the stem, according to some authors.
Odor and Taste: Not distinctive.
Chemical Reactions: Flesh dull orange with KOH, olive green with iron salts.
Spore Print: Olive brown.
Microscopic Features: Spores 10-14 x 3-5 µ; smooth; subfusoid.
REFERENCES: Krombholz, 1836. (Saccardo, 1888; Smith & Thiers, 1971; Smith, Smith & Weber, 1981; Phillips, 1991/2005; Metzler & Metzler, 1992; Both, 1993; Bessette, Roody & Bessette, 2000; McNeil, 2006; Binion et al., 2008.) Herb. Kuo 06269510, 07200202, 08240211, 07120804.
Xerocomus rubellus is a synonym.
Further Online Information:
The "Campellus" Calculator
The calculator assigns points for Boletus rubellus ("R") and Boletus campestris ("C"). Calculate the total points for "R" and "C," then base your identification on the species receiving the most points. If the difference between your point totals is less than 2 and you have not measured the spores, you should consider your results tentative. You should also consider the possibility that DNA studies will eventually conflate these two species (or split them into 10 species), and your effort will have been pretty pointless.
Cite this page as:
Kuo, M. (2004, November). Boletus rubellus. Retrieved from the MushroomExpert.Com Web site: http://www.mushroomexpert.com/boletus_rubellus.html