Albatrellus subrubescens

Description

Albatrellus subrubescens is a species of polypore fungus in the family Albatrellaceae. The fruit bodies of the fungus have whitish to pale buff-colored caps. On the underside of the caps are tiny light yellow to pale greenish-yellow pores, the site of spore production. When the fruit bodies are fresh, the cap and pores stain yellow were exposed, handled, or bruised.

The species is found in Asia, Europe (rare), and North America, where it grows on the ground in deciduous or mixed woods, usually in association with pine trees.

This mushroom has been recently reported edible when young and not poisoned at all (Guida ragionata alla commestibilità dei funghi September 2021 Edition: 1stEditor: Regione Piemonte (con il patrocinio di/under the auspices of) ISBN: 979-12-200-9297-5 - Nicola Sitta). There are no cinfirmed clinical cases of poisoning from this mushrooms. Instead it could be of bitter and unpleasant taste if not young mushrooms are collected. But Ultimate Mushroom doesn't recommend collecting and eating this fungus because of its similarity to numerous poisonous species.

Mushroom Identification

1. Cap

   7 to 18 cm wide, cream-colored, reddish and purple, with orange bruises; bulging, quickly flattened and sunken in the middle, twisted and lobulated; margins wavy and mostly kept curved; skin cracks in old age or in very dry weather. Usually, several uppercase letters are merged and tightly joined.

2. Stem

   3 to 7 cm high, and 1 to 3 cm in diameter. Creamy white or slightly rufous, turning orange where bruised.

3. Pores

   White or creamy yellow; irregularly oval; tubes decurrent; 2 to 3 per mm.

4. Spores

   Ellipsoidal to ovoid, 3.4-4.7 by 2.2-3.4 µm; amyloid, finely warty.

5. Spore Print

   White.

6. Season

   July to December.

Look-Alikes

1. Albatrellus ovinus

   Has a lighter cap surface and does not turn orange when bruised. A reliable distinction between these two very similar species requires a microscopic examination of the spores.

2. Albatrellus tianschanicus

   Described from the Altai Mountains in East-Central Asia, and the Japanese species Albatrellus cantharellus. Unlike A. subrubescens, these species have hairy scales on the surface of their caps, and the scales are darker than the spaces between the scales. Also, the scales of A. subrubescens are not much darker than the area between the scales. Both of these Asian species have larger spores than A. subrubescens: those of A. cantharellus are 4.5–7 by 4–5.5 µm, while those of A. tianschanicus are 5–7 by 4–5 µm.

3. Albatrellus confluens

   Has caps that are pinkish-buff to pale orange, and white flesh that dries to a pinkish-buff; it has a bitter taste, or like cabbage. The spores of A. confluens are weakly amyloid. Additional differences distinguishing Albatrellopsis confluens from A. subrubescens include the presence of clamp connections in the context hyphae, and mycelium on the base of the stem.

4. Albatrellus citrinus

   The European fungus A. citrinus, originally considered a morphotype of A. subrubescens, was described as a new species in 2003. It is distinguished from A. subrubescens morphologically by its smaller caps (up to 7 cm (2.8 in) in diameter), the yellowish bruising of the caps with age or after handling, and the absence of violet spots on the cap. A. citrinus associates with spruce rather than pine, and requires calcareous (lime-rich) soil.

History

The species was first described as Scutiger subrubescens in 1940 by American mycologist William Merrill based on a collection he found under an oak tree near Gainesville, Florida in November 1938.

In 1947 he transferred them to Polyporus. Josiah Lincoln Lowe examined Murrill's typeface material and found it to be no different from Albatrellus confluens.

In 1965, Zdeněk Pouzar collected some collections from Bohemia (now the Czech Republic) and described them as a new species (Albatrellus similis), unaware of the similarities to Murrill's Florida specimen. Further investigation revealed that A. similis was identical to Murrill's Scutiger subrubescens, whose epithet Pouzar transferred to Albatrellus.

In 1974, Pouzar recognized that Lowe's Albatrellus confluens was different from A. subrubescens.

The specific epithet subrubescens, "reddish", is derived from the Latin words sub ("less than") and rubescens ("growing red").

Albatrellus subrubescens Bioactive Compounds

Albatrellus subrubescens contains the bioactive compound scutigeral, which has antibiotic activity. This chemical—also found in the related species A. ovinus—may contribute to the mushroom's toxicity by disturbing the body's intestinal flora. Scutigeral interacts selectively to the dopamine receptor D1 subfamily (the most abundant dopamine receptor in the central nervous system, regulating neuronal growth and development, and mediating some behavioral responses).

A 1999 publication suggested that scutigeral has agonistic activity at vanilloid receptors (a receptor found on sensory nerves in mammals); specifically, that it affects the uptake of calcium in the neurons of rat dorsal root ganglia. Later reports failed to corroborate this pharmacological activity.

One 2003 study reported that scutigeral acts as a weak antagonist on the human vanilloid receptor VR1, while another study published that year did not find any activity.

Synonyms

1. Scutiger subrubescens Murrill (1940)

2. Polyporus subrubescens (Murrill) Murrill (1947)

3. Albatrellus similis Pouz. (1965)

4. Scutiger ovinus var. subrubescens (Murrill) L.G.Krieglst. (1992)

5. Albatrellus ovinus var. subrubescens (Murrill) L.G.Krieglst. (2000)

Photo sources:

Photo 1 - Author: Ryane Snow (snowman) (CC BY-SA 3.0)

Photo 2 - Author: Gerhard Koller (CC BY-SA 3.0)