E-Flora BC: Electronic Atlas of the Flora of British Columbia

Summary:
Also listed in Boletes category. Most or all of the observations of this species on the west coast of North America are Phylloporus arenicola. Features are a dry minutely velvety brown to reddish cap that looks like a Boletus, and thick yellow gills. The subspecies is not specified for the Arora description below (note that he says the gills typically bruise green or blue but sometimes not at all), but Bessette''s description is for ssp. americanus Singer (without that color change). Ssp. foliiporus (Murrill) Singer has a bright yellow gill-like surface that stains bluish to greenish when bruised and a cinnamon to dark pinkish brown cap, (Bessette). P. rhodoxanthus ssp. albomycelinus Snell and Dick from eastern North America (with white basal mycelium) has been renamed P. leucomycelinus Singer.

P. rhodoxanthus is reported from WA by O''Dell, and is not uncommon on foray lists in BC (often blue-staining), with collections at Pacific Forestry Centre and University of British Columbia. There are also collections from WA at University of Washington. Bessette gives the range of ssp. americanus as eastern Canada south to FL, west to CA. Both(1) says ssp. foliiporus is recorded from FL north to NJ. (Incidentally Both(1) says that the photo in Phillips(1) p. 127 of P. foliiporus is R. boletinoides).

Cap:
2-5(12)cm across, broadly convex to flat or with uplifted margin when old; "dull brown to olive-brown or yellow-brown in one form, red to reddish-brown in another", "sometimes developing pallid to yellowish cracks or fissures"; surface "dry, minutely velvety to nearly smooth", (Arora), 2.5-10cm across, obtuse to convex at first, becoming nearly flat and sometimes shallowly depressed; "color variable, dark red, dull red, reddish yellow to reddish brown or olive brown"; dry, somewhat velvety, often cracked to cracked-areolate [cracked like dried mud] when old; margin typically with narrow band of sterile tissue, (Bessette)

Flesh:
thick; pallid to yellowish, (Arora), whitish to pale yellow, tinged reddish under cap surface, (Bessette)

Gills:
gill-like structures adnate to decurrent but sometimes seceding, widely spaced, broad, fairly thick, sometimes forked or with cross veins; "bright yellow to ocher, typically bruising green or blue (but often slowly, sometimes not at all), sometimes also staining brownish", (Arora), with strong gill-like structures, sometimes pore-like near stem, decurrent, subdistant to distant, sometimes forked, strongly interveined, separating cleanly from cap; bright yellow at first, becoming yellow to golden yellow and finally ocher in age, not turning blue when bruised, (Bessette)

Stem:
3-10cm x 0.4-1(1.5)cm, equal or narrowing downward, solid, "yellow to dingy yellowish-buff or reddish", often stained dingy brown or reddish-brown in lower part; smooth, dry, (Arora), 3-9cm x 0.5-1.3cm, nearly equal or ventricose at base; yellow with reddish tinges; often with distinct ribs near top, "scurfy or punctate with small reddish brown dots and points"; with yellow basal mycelium, (Bessette)

Veil:
absent

Odor:
not distinctive (Arora), not distinctive (Bessette)

Taste:
not distinctive (Arora), not distinctive (Bessette)

Microscopic spores:
spores 9-15 x 3-6 microns, narrowly elliptic to spindle-shaped, smooth (Arora), spores 8-14 x 3-5 microns, elliptic to fusoid, smooth, pale yellowish (Bessette)

Spore deposit:
brown to yellowish-tinged or olive-tinged (Arora), yellowish ochraceous (Bessette), orange-brown to yellowish brown (Miller)