The North American Species of Pholiota

11. Pholiota aurea (Fr.) Kummer, Der Führer in die Pilzkunde p. 85. 1871.

Agaricus aureus Fries, Syst. Myc. 1: 241. 1821.
Togaria aurea (Fr.) W. G. Smith, Syn. British Basid. p. 122. 1908.
Phaeolepiota aurea (Fr.) Konrad & Maublanc, Icon. Select. Fung. 6: 11. 1924-1928.
Agaricus vahlei Fries, Syst. Myc. 1: 240. 1821.
Lepiota pryrenacea Quélet, Champ. Jura & Vosges supp. 16, p. 1 (reprint). 1887.

Illustrations: Text figs. 9-10; pls. 5, 6.

Pileus 7-20 (30) cm diam., convex to obtusely campanulate young, expanding to obtusely umbonate or nearly plane finally; colors orange-buff to orange-ochraceous in buttons, usually becoming paler in age, rarely merely ochraceous; surface dry, granulose to unpolished (in age when most of the veil particles have weathered away); margin often appendiculate with veil remnants. Context pallid and unchanging when cut or bruised, firm, moderately thick in the disc; odor mild to slightly pungent, taste mild to slightly astringent.

Lamellae pallid in buttons, becoming more or less concolorous with or darker than pileus at maturity, adnate or at times with a short decurrent tooth, moderately broad, close, edges entire and concolorous.

Stipe 10-15 (25) cm long, (1.5) 3-5 (6) cm in diam. at apex, enlarging downward to subclavate; more or less concolorous with the pileus though sometimes darker at the apex; surface dry and unpolished; smooth and glabrous above the annulus, below the latter peronate with a covering similar to that of the pileus; annulus flaring, membranous, persistent to mid-maturity, finally becoming pendulous and disappearing in extreme age; the peronate sheath separable to the base of the stipe. Context whitish or somewhat streaked with orange down the center and the cortex longitudinally fibrous, stuffed becoming hollowed; base of stipe white mycelioid and with a few short white poorly developed rhizomorphs.

Spore deposit light yellow-brown to orange-buff. Spores 10.7-13 (14) x 5-6 µ, yellowish to clay-color in KOH and with one large central oil drop, somewhat elliptic in face view, in profile somewhat inequilateral, inamyloid, smooth or some with minute markings, wall thin and many spores collapsing, no germ pore evident under oil immersion.

Basidia hyaline to pale brownish in KOH, usually 4-spored, clavate, thin-walled, occasionally with a highly refractive body as revived in KOH. Pleurocystidia absent or rarely clavate-mucronate and brownish in KOH, measuring 26-30 x 7.5-8.5 µ. Cheilocystidia none (edge entirely fertile).

Gill trama of subparallel to parallel hyphae with yellowish to brownish thin to slightly thickened walls as revived in KOH; subhymenium of narrow (2-3 µ) non-gelatinous hyaline hyphae. Epicutis of pileus of inflated often isodiametric cells 12-25 µ diam., smooth or with one to several short finger-like or knob-like projections over the apex of the terminal cells of the chain, the walls thin to slightly thickened, pale yellowish in Melzer's reagent but orange-cinnamon in KOH. Clamp connections present.

Habit, Habitat, and Distribution: Caespitose-gregarious often near the edges of roads under Alnus, September to October, Pacific Northwest to Alaska, rare, but when it fruits it is found in quantity.

Observations: As is indicated in the synonymy, this species has been placed in a number of genera. We did not suspect what we now regard as its true relationships until after completing our study of this subgenus. Both P. erinaceella and P. granulosa in particular have basically the same type of pileus epicutis with the cells having the same type of KOH reaction. It can be characterized as the Cystoderma-type, which implies that not all the cuticular cells are sphaerocysts. In Flavidula there are two major lines of development. The first leads to the type of cutis found in P. erinacea where there is no disarticulation of the cutis cells and there is a tendency for the hyphae to develop thick colored walls. The second line is to the Cystoderma-type. Singer (1963) placed Togaria with aurea as the only species near Lepiota. We believe the resemblance to be superficial. The spores in KOH are pale tawny and thin-walled more like a Tubaria spore than any other type. But Tubaria also demonstrates the development of the Cystoderma-type pileus cutis. The large size of the basidiocarps should not influence any one to use this feature to establish relationships here. It has been amply shown throughout this paper that size is of no value in delimiting infrageneric or generic groups among pholiotoid fungi. In P. aurea the ornamentation of the spores is very minute, and in a way contradicts our definition of "spores smooth" for the genus. But here one has a choice of which spores he wishes to emphasize, the smooth ones or those with ornamentation, and this of course tends to vitiate the character as one of importance as far as relationships are concerned. The situation here is more like that in Rhizopogon, another genus of smooth-spored fungi, where, if one wishes, it can be claimed that some of the species have slightly ornamented spores. It should also be kept in mind that as far as P. aurea is concerned, Tubaria, to which it might be truly related, is a genus containing species with both smooth and ornamented spores. Thus in our opinion, a monotypic genus here serves no useful purpose either from a practical or theoretical consideration, and we have placed the species in line with previous tradition.

In Europe P. aurea is considered a good edible species but in Alaska Wells and Kempton (1965) have reported cases of "mild" poisoning from it. Bach (1956) made an excellent study of the physiology and ecology of this species. From Bach's study it is apparent that the fungus is not restricted to a single forest tree, and we would judge that its occurrence under alder in the Pacific Northwest is indicative of a habitat filled with nutrients rather than one indicating a symbiotic relationship with the alder.

Material Examined: WASHINGTON: Imshaug 1801; Smith 3050, 3117, 3355 30448, 30859, 31491, 39843. CANADA (BRITISH COLUMBIA) Odell 1922. Reported from Alaska by Wells and Kempton (1965) and their specimens examined.