Phylloporus rhodoxanthus
Description
Phylloporus rhodoxanthus is a species of fungus in the family Boletaceae. Caps start convex (domed) with an inrolled margin, expanding and flattening up to 120mm across. Commonly, the caps are 'biscuit' brown, smooth and dry, but often wavy or contorted. The cap will sometimes age to be funnel-shaped. With age, the surface of some caps will crack into a tessellated pattern, making identification somewhat confusing, but blue bruising of the damaged flesh is a sure identification feature. Fresh gills are pale to bright yellow, and supple, but dry out with age to a brownish-yellow. Gills can extend down the stem.
The fruit bodies of Phylloporus rhodoxanthus grow on the ground singly or in small groups in deciduous forests, especially those with oak and pine. The species has a wide distribution in North America, where it fruits from July to October. It is also known from Asia (China, India, and Taiwan), Australia, and Europe.
In addition to the different colored mycelium, some sources suggest that Phylloporus rhodoxanthus has brighter yellow baby gills & duller old man gills than Phylloporus rhodoxanthus leucomycelinus. Beyond that, they are very hard to tell apart.
The species was first described as Agaricus rhodoxanthus by Lewis David de Schweinitz in 1822. Giacomo Bresadola transferred it to Phylloporus in 1900.
Common names: Gilled Bolete, Goldgills.
Mushroom Identification
Ecology
Mycorrhizal with hardwoods, especially oaks and Beech; growing alone, scattered, or gregariously; summer and fall; widely distributed in North America.
Cap
2.5-10 cm; convex, becoming broadly convex to more or less flat; dry; fairly smooth, sometimes beginning to crack in age; red to reddish-brown, or olive-brown to brown; fading; the margin inrolled when young, and with a small projecting sterile portion.
Gills
This brown mushroom has yellow gills running down the stem. It becomes dirty with age and does not bruise blue. It is thick and sometimes forked, sometimes with cross-veins.
Stem
3-9 cm long; .5-1.5 cm thick; more or less equal, or tapering to base; sometimes appearing "ribbed" near the apex at the termination points of the gills; yellowish, with reddish dots and scruffies; basal mycelium yellow.
Flesh
White to pale yellow.
Odor and Taste
Odor not distinctive; taste mild.
Chemical Reactions
Cap surface blue with ammonia.
Spore Print
Yellowish to dirty yellow.
Microscopic Features
Spores 8-14 x 3-5 µ; smooth; long-elliptical to sausage-shaped.
Similar Species
Phylloporus leucomycelinus is frequently confused, especially since their distributions overlap. The latter species can be distinguished by the presence of white mycelium at the base of its stem.
Medicinal Properties
Antitumor effects. Polysaccharides extracted from the mycelial culture of P. rhodoxanthus and administered intraperitoneally into white mice at a dosage of 300 mg/kg inhibited the growth of Sarcoma 180 and Ehrlich solid cancers by 90% and 80%, respectively (Ohtsuka et al., 1973).
Cooking Notes
The mushrooms are edible and considered good by some. The flavor has been described as "tender and nutty", and drying the fruit bodies first enhances the flavor. Suitable culinary uses include sauteing, adding to sauces or stuffings, or raw as a colorful garnish. They are used to make mushroom dyes of beige, greenish beige, or gold colors, depending on the mordant used.
Photo sources:
Photo 1 - Author: JJ Harrison (https://www.jjharrison.com.au/) (CC BY-SA 3.0)
Photo 2 - Author: I. G. Safonov (IGSafonov) (CC BY-SA 3.0)
Photo 3 - Author: I. G. Safonov (IGSafonov) (CC BY-SA 3.0)
Photo 4 - Author: Bob (Bobzimmer) (CC BY-SA 3.0)
