Calcipostia guttulata

What You Should Know

Calcipostia is a monotypic genus of fungi belonging to the family Fomitopsidaceae. The only species is Calcipostia guttulata. It is a rare mushroom with a small to medium annual polypore. Cap fan-shaped, flattish at maturity, white, smooth but with scattered tiny, circular depressions; bruising rusty-brown; pale brown overall in age. Pores are cream-colored. Saprophytic as well as parasitic.

It has a soft, white fruit body. Circular depressions may be filled with liquid when fresh. Pores are very small, circular to angular. Bitter taste.

Habitat solitary or in small clusters on rotting conifer wood; also fruiting at the base of infected live Sitka spruce.

Distributed in the boreal circumpolar coniferous zone of North America, from Arizona to Alaska and east and south of the Appalachians.

Other names: Dråbe-kødporesvamp (Denmark), Drobnoporek łzawiący / Białak łzawiący (Poland).

Calcipostia guttulata Mushroom Identification

1. Fruit Bodies

   Large, 20–150mm broad, extending 30–120mm and relatively thin, 4–8mm thick, semi-circular, elongated, sessile or attached laterally by a tapered part to the substrate; white, with age indistinctly pink zonate, in injured places also turning violet, purple-brown; on the pileal margin and from the tubes of young sporocarps appear guttation drops, which on drying up leave pitted surface.

2. Pores

   White, with a deep-blue-green tint, dry also with lilac tint; 4–6 per mm.

3. Taste

   Bitter.

4. Spore Print

   White.

5. Habitat

   It occurs on the stumps of conifers, spruce, pine, less often on deciduous stumps, singly or in overlapping groups. Grows all year round.

6. Microscopic Features

   Spores 4-5 x 2-2.5 microns, short-cylindric to oblong, smooth, inamyloid, colorless; basidia 4-spored, 15-20 x 5-6 microns, clavate, with basal clamp; cystidia none, cystidioles 13-18 x 4-5 microns, fusoid, not projecting beyond basidia, with basal clamp; hyphae monomitic, hyphae of context with clamp connections, some very thick-walled with a narrow lumen, occasionally nodose-septate, commonly branching opposite the clamp, 4-8(12) microns wide, some with thin to partially thickened walls, with abundant clamp connections and occasional branching, 3-6 microns wide, gloeoplerous hyphae also present, 5-10(14) microns wide, "staining bright red in phloxine, thin-walled, with occasional distorted clamps, sinuous and with constrictions and swellings", hyphae of trama mostly of the thin-walled non-staining type.

Calcipostia guttulata Look-Alikes

1. Postia stiptica

   Similar in appearance and microscopically. Has a rough cap that usually has small, black dots on the surface.

2. Tyromyces chioneus

   Has a mild taste, and typically lacks these features of C. guttulata: saucer-shaped depressions, drops of liquid on most fresh fruitbodies, and a faint greenish cast on the pore surface.

Calcipostia guttulata Synonyms

• Postia guttulata (Peck) Julich, 1982

• Oligoporus guttulatus (Sacc.) Gilb. & Ryvarden

• Polyporus grantii Lloyd

• Polyporus guttulatus Sacc.

• Polyporus maculatus Peck

• Polyporus substipitatus (Murrill) Murrill

• Polyporus tiliophilus (Murrill) Sacc. & Trotter

• Postia guttulata (Peck) Jülich

• Spongiporus guttulatus (Sacc.) A.David

• Tyromyces guttulatus (Sacc.) Murrill

• Tyromyces stipticus subsp. guttulatus (Peck) Domanski, Orlos & Skirg., 1967

• Tyromyces substipitatus Murrill

• Tyromyces tiliophilus Murrill

Sources:

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