Pholiota squarrosa, commonly known as the Shaggy Scalycap, is one of the most distinctive and easily identified species in the genus Pholiotina. Its erect and recurved scales on its cap and stalk in addition to the yellow-brown coloration and brown spore print easily set it apart from the rest.[i]
This species was first described in the latter half of the 18th century by the Swedish-born German scientist Christian Ehrenfried Weigel. Weigel termed this species Agaricus squarrosus similar to most other gilled mushroom species of the time. It was not until almost a century later that in 1871 German mycologist Paul Kummer reclassified the species under its current scientific name, Pholiotina squarrosa.
Etymology of Pholiota squarrosa is Greco-Latin. The name “Pholiota” is derived from the Greek word “pholis,” which means “scale,” referring to the scaly appearance of the cap and stalk of the mushroom. The species name “squarrosa” comes from the Latin word “squarrosus,” which means “scaly” or “rough”, also referring to the shaggy appearance of the mushroom, which is covered in brownish scales. Therefore, the scientific name Pholiota squarrosa can be translated as “Scaly Pholiota with rough scales.”
Identification and Description[ii],[iii],[iv]
Cap: The cap of Pholiota squarrosa measures 3-12 cm in diameter. It is convex to bell-shaped when young, but with age becomes flat to slightly depressed with a low, broad hump. The surface of the cap is dry and covered in shaggy, recurved brownish-orange scales that are more densely packed near the center. The margin of the cap may sometimes have a remnant of the veil, especially in young specimens.
Flesh: The flesh of Pholiota squarrosa is thick, fibrous, and rather pliant. The flesh is white to pale yellow.
Gills: The gills of this mushroom are narrow, broad, and slightly decurrent, running down the stem. They are initially a pale yellow color but become greenish-tinged and then a rusty brown color as the mushroom and its spores mature.
Stalk: The stalk of Pholiota squarrosa is relatively long, equally cylindric, or sometimes tapered towards the base, and measures between 4-12 cm in length and 0.3-1.5 cm in diameter. Similar to the cap, it is covered in brownish-orange down-curved scales that become more sparse towards the base of the stalk. The stalk is also fibrous, tough, and dry and may have a slight curve or bend.
Spores: The spores of this species are elliptical to oval in shape, smooth, and with a pore at the tip. They measure between 7-10 µm long and 4-6 µm wide and are rusty brown in color.
Spore Print: The spore print of Pholiota squarrosa is dull cinnamon-brown to rusty-brown color.
Odor: This species has a distinctive, somewhat unpleasant odor that has been described as garlicky or an onion-like scent. The odor is often more noticeable when the mushroom is fresh, and may become less distinct as it dries out or ages.
Edibility: Pholiota squarrosa is considered an edible mushroom, but it is not commonly consumed due to its tough texture and bitter taste. Furthermore, the consumption of this species has been known to cause severe gastrointestinal discomfort in some people. As such, eating this species is not recommended.
Habitat: Pholiota squarrosa is a saprophytic mushroom. It can be found growing in small clusters at the base of dead or dying hardwood trees, such as aspen, spruce, oak, beech, maple, and birch, as well as on decaying wood and stumps. It prefers moist and cool environments and can be found growing in forests, woodlands, and parks.
Range: Pholiota squarrosa has a wide geographic distribution and can be found in various parts of the world. It is a common mushroom in North America, Europe, and Asia, and has also been reported in Australia and New Zealand. In North America, it is commonly found in eastern and central regions, including the northeastern United States, the Great Lakes region, the Sierra Nevada, and parts of the southeastern United States.
Fruiting Season: The fruiting season for Pholiota squarrosa is typically from late summer to fall (July-October).
There are several species of mushrooms that can be easily confused with Pholiota squarrosa due to their similar appearance. Some of the most common look-alikes include:
- Pholiota squarrosoides – this species has a slime layer and lacks the greenish tones on the gills.
- Pholiota flammans – this species has dry scales that are a brilliant yellow color.
- Pholiota terrestris – as the name suggests this species typically grows on the ground rather than. on trees.
- Galerina marginata – this is a highly toxic species similar in size, shape, and color. However, G. marginata has a smooth stem, lacks the shaggy scales of P. squarrosa, and has a ring on the stem.
- Pholiota adiposa – this species has a more reddish-brown cap and stem, and a more greasy or slimy texture.
- Pholiota aurivella – this species has a more yellowish-brown cap and is smaller.
Phallus indusiatus Safety[vi]
The Scaly Pholiota is considered edible by some, but as mentioned it has been known to cause severe gastric discomfort in some people within an hour after having been eaten. Furthermore, this species can easily be confused with highly toxic Galerina marginata which contains deadly amatoxins, which can cause liver and kidney failure if ingested.
As such it is best to avoid consuming this species despite its status as “edible”. Additionally, it is crucial to properly identify this species before consuming it and to consult an experienced mycophile if there is any doubt about its identity.
[i] McKnight, K. H., & McKnight, V. B. (1998). Shaggy Scalecap. A field guide to mushrooms, North America. (Pp. 272-273) Houghton Mifflin.
[ii] Lincoff, G. (1981). Scaly Pholiota. In National Audubon Society Field Guide to North American mushrooms (pp. 716–717). Knopf.
[iii] First Nature. Pholiota squarrosa (Weigel) P. Kumm. – Shaggy Scalycap
[iv] Emberger, G. (2008). Pholiota squarrosa. Messiah University.
[v] Kuo, M. (2022, March). Phallus indusiatus.
[vi] D. Arora (1986) Pholiota squarrosa (Scaly Pholiota). “Mushrooms Demystified: A Comprehensive Guide to the Fleshy Fungi,” (p. 196) Ten Speed Press, Berkeley