|Major Groups > Boletes > Boletus > Retiboletus ornatipes|
by Michael Kuo
This is a striking bolete with a yellow, coarsely reticulate stem (the species epithet ornatipes means "ornate-stemmed") and a yellow to brown cap. Its surfaces do not bruise blue, and its cap surface turns dark reddish brown with KOH. It grows under hardwoods in eastern North America.
Retiboletus ornatipes has traditionally been called "Boletus ornatipes," but recent DNA results (Binder & Bresinsky, 2002) support placing it, along with Retiboletus griseus and a few other mushrooms, in a separate genus. The study also found support for at least three ornatipes-like species, two of which are apparently more southern (ranging from North Carolina to Costa Rica) and may correspond to "Boletus retipes," which has traditionally been separated on the basis of its southerly distribution and the presence of yellow powder on the young caps. However, the researchers were unable to find morphological separators that reliably predicted the three species.
Ecology: Mycorrhizal with hardwoods, especially oaks; growing alone, scattered, or gregariously; often growing in moss; summer and fall; widely distributed in eastern North America.
Cap: 4-16 cm; convex, becoming broadly convex or nearly flat in age; dry; bald or felty, sometimes nearly velvety; variable in color, ranging from yellow to pale gray to yellow brown or olive brown; frequently yellow along the margin.
Pore Surface: Bright yellow, becoming olive yellow with age; not bruising, or bruising brighter yellow or orangish (rarely brownish); with 2-3 round pores per mm; tubes to 15 mm deep.
Stem: 6-15 cm long; 1-2.5 cm. thick; more or less equal, sometimes tapered towards the top or (more frequently, in my experience) the bottom; prominently and coarsely reticulate with a yellow reticulum that becomes brownish with age or on handling; bright yellow, discoloring brownish in age; bruising orangish yellow; solid; basal mycelium yellow.
Flesh: Yellow (light yellow, becoming golden yellow when cut), not staining blue on exposure.
Odor and Taste: Odor not distinctive; taste mild or somewhat bitter.
Chemical Reactions: Ammonia orangish to pale brown on cap surface; negative to pale brown on flesh. KOH dark reddish brown on cap surface; orangish on flesh. Iron salts negative on cap; negative to whitish on flesh.
Spore Print: Olive brown.
Microscopic Features: Spores 9-14 x 3-4 µ; smooth; subfusoid. Hymenial cystidia fusoid-ventricose; necks filled with yellowish contents when dried material is mounted in KOH.
REFERENCES: (Peck, 1901) Binder & Bresinsky, 2002. (Saccardo, 1888; Coker & Beers, 1943; Singer, 1947; Snell & Dick, 1970; Smith & Thiers, 1971; Grund & Harrison, 1975; Smith, Smith & Weber, 1981; Arora, 1986; Phillips, 1991/2005; Lincoff, 1992; Both, 1993; Barron, 1999; Bessette, Roody & Bessette, 2000; Binder & Bresinsky, 2002; Roody, 2003; McNeil, 2006; Miller & Miller, 2006; Kuo, 2007; Ortiz-Santana et al., 2007; Binion et al., 2008.) Herb. Kuo 08309702, 05300408, 07240801.
Boletus ornatipes is a synonym.
Further Online Information:
Cite this page as:
Kuo, M. (2010, April). Retiboletus ornatipes. Retrieved from the MushroomExpert.Com Web site: http://www.mushroomexpert.com/retiboletus_ornatipes.html