The North American Species of Pholiota

Subgenus Flavidula subg. nov.

Pileus siccus, fibrillosus vel squamulosus, luteus, luteofulvus, fulvus vel badius. Stipes glaber, fibrillosus, granulosus vel non squarroso-squamulosus. Typus: Pholiota curvipes.

Species with a pileus trichodermium of non-gelatinous hyphae and typically having the cells more or less inflated or often sphaerocyst-like are placed here if in addition the spores are tawny to cinnamon-brown or dark yellow-brown in KOH and have smooth walls. In some species the epicutis of the pileus consists of innate appressed non-gelatinous hyphae. A germ pore may or may not be present at the spore apex, and if present it is usually so small that a 1.4 N.A. oil immersion lens is often needed to see it clearly. The cells of the hyphae forming the trichodermium in section Flavidula may be thin or thick-walled, and smooth or incrusted, but become a dark rusty brown color in KOH. This latter reaction we consider an important feature of the subgenus. An annulus may or may not be present. The pileus generally appears dry and appressed fibrillose to echinate-squamulose. Species with a hygrophanous pileus are not admitted to section Flavidula. Species having pale colored spores (yellowish to nearly hyaline) and with the wall thin are retained in Tubaria. Clamp connections are present in all but P. cinchonensis. No species with a gelatinous layer in the pileus cuticle is admitted. As here defined, many of the species included by Singer (1956) in Phaeomarasmius are excluded because of the combination of pale colored spores and hygrophanous pilei. We are here restricting Phaeomarasmius to the small species with eccentric stipes in addition to the characters emphasized by Singer. This interpretation is consistent with the features of the type species. However a detailed critical study of Tubaria and Phaeomarasmius must now be made to more clearly delimit them from Pholiota. For one thing, E M photographs of the spore-wall are badly needed since the layering in the wall is important in determining generic limits. In the present work we have tried to bring together those taxa which we believe connect so well to Pholiota that there is no valid reason for excluding them. Actually many of them were described in Pholiota and Flammula originally. Species with chrysocystidia are arbitrarily excluded from this subgenus. They are found in Phaeonaematoloma and Pholiota. However, brown cells (basidioles and/or basidia) are often encountered in species of Flavidula. Not infrequently these can be observed bearing spores, and so unquestionably are true basidia. To us it is obvious that subg. Flavidula connects to Tubaria to the extent that it will take a very careful study to properly dispose of all the questionable species. The subgenus is also very closely related to Galerina sect. Inoderma. The only way to accurately distinguish between them is to place generic emphasis on the line delimiting the plage of the spore in the Galerinae, but at the same time one must point out that many species of Galerina in other sections have truly smooth spores and that a number of these show Pholiota characters, such as the gelatinous subhymenium (in the G. sideroides group).

Section Flavidula

Characters as given in the description of the subgenus.

Key to Stirps

1. Pileus appressed fibrillose when young, not hygrophanous, becoming appressed squamulose to diffracted scaly in age; epicuticular hyphae not greatly inflated
Stirps Curvipes
1. Not as above
2
2. Pileus cuticle granulose-tomentose (of chains of inflated cells, these often disarticulating to produce the granulose texture) or the spores large (9-12 x 5.5-7 µ), or both
Stirps Aurea
2. Not as above
3
3. Clamp connections absent; known from Jamaica
3. Not as above—clamps readily demonstrated
4
4. Pleurocystidia present
Stirps Corticola
4. Pleurocystidia absent
5
5. Hyphae of pileus epicutis mostly thick-walled
Stirps Erinacea
5. Hyphae of pileus epicutis not as above
Stirps Curcuma

 

Stirps Curvipes

The epicutis of the pileus consists of hyphae becoming cinnamon in KOH, but the cells are less inflated than those in the other stirpes and the walls are not as coarsely or extensively incrusted or ornamented. The gradations between species in this stirps are such that one might regard it as a single variable taxon. A critical study of the behavior in culture of these variants is badly needed because the apparent introgression is of a pattern common to the fleshy fungi generally often in groups not readily culturable. Lacking this approach, we present here the taxa as we can recognize them in nature. The color of the veil, Singer to the contrary notwithstanding, does not distinguish this stirps from the others (except for stirps Cinchonensis).

Key

1. Stipe about 2 mm diam.; pileus ferruginous and finely squamulose
1. Not as above
2
2. Taste mild; lamellae broad and at maturity subdistant
2. Taste of raw context distinctly bitter
3
3. Stipe (3) 4-10 (12) mm. thick; lamellae narrow and crowded
3. Stipe 2.5-3 mm. thick; caespitose; lamellae broad and subdistant

 

Stirps Aurea

In this stirps, with the exception of P. fulvella, it is known that the epicutis of the pileus contains many cells more or less isodiametric to keg-shaped. In this respect and in the KOH reactions there is a strong parallel to Cystoderma of the Tricholomataceae. P. fulvella is placed here because of the large spores and lack of cheilocystidia.

Key

1. Spores 9-13 (14) µ long
2
1. Spores shorter
3
2. Stipe 3-4 mm. thick
2. Stipe 3-5 cm thick
3. Cheilocystidia clavate to subglobose, 20-30 x 9-18 µ
3. Cheilocystidia (at least many of them) with a flexuous pedicel and clavate at the tip, or fusoid-ventricose
4
4. Cheilocystidia (40) 50-115 x 3.5-6 x 9-16 µ
4. Cheilocystidia 28-40 x 7-11 µ
4. Cheilocystidia 26-40 X 8-16 µ; Caulocystidia often boomerang-shaped

 

Stirps Cinchonensis

Stipe with a white annulus; clamp connections apparently absent.

Key

1. Only one species

 

Stirps Curcuma

The pileus cuticle is more of a trichodermium in this stirps than in the others, including the feature that the cells do not disarticulate.

Key

1. Growing on hemlock; odor when fresh aromatic; taste resembling that of birch twigs
1. Not as above
2
2. Pileus 2-6 mm broad; spore wall up to about 0.5 µ thick
2. Pileus 1-3 cm broad; spore wall closer to 0.25 µ thick
3
3. Pileus pale yellow to pale tan when fresh; spores with a distinct pore
3. Not as above
4
4. Cheilocystidia clavate to vesiculose, walls typically yellow in KOH  (see P. granulosa also)
4. Cheilocystidia utriform, fusoid-ventricose, subcylindric, etc. but not as above
5
5. Lamellae distant and arcuate
5. Lamellae close
6
6. On conifer wood; lamellae subdistant; cheilocystidia elongate-pedicellate with enlarged apex     
6. On hardwood; lamellae close; cheilocystidia clavate, utriform to fusoid-ventricose

 

Stirps Corticola

This group is featured by species having pleurocystidia. P. erinacea of the next stirps shows these in some collections but not in others.

Key

1. Spores 6-7 x 3.5-4 µ
1. Spores larger
2
2. Pleurocystidia 26-30 x 5-8 µ, clavate-rostrate
2. Pleurocystidia 40-60 x 10-16 µ

 

Stirps Erinacea

This stirps features characteristically thick-walled elements in the trichodermium of the pileus and is peripheral in the genus.

Key

1. Only one species