Cryptoporus volvatus

🏷️ Description

Meet Cryptoporus volvatus, a fascinating and unique fungus that thrives on rotting conifer sapwood, often in the wake of pine bark beetle infestations. This peculiar polypore, also known as the cryptic globe fungus, is easily recognized by its cream or tan fruiting body, which can be 2–6 cm across. At first glance, it might resemble a puffball on wood, but look closer! When cut, the inside reveals the classic tubes of a polypore, a subtle reminder of its true nature.

The fungus’s spore dispersal strategy is where it truly shines. Spores are trapped under a protective flap of tissue. As the fungus matures, tiny openings appear in the membrane, and wood-boring beetles—drawn by the spores—chew through, helping to disperse them. These spores hitch a ride to new dead trees, ready to take root and grow. Interestingly, even the white-headed woodpecker plays a role in spreading the spores while hunting for beetles! 🦠🐦

Primarily found on conifers that have been weakened by fire, disease, or beetle attacks, this fungus makes its appearance only within a year or so of a tree's death. The distribution stretches from Alaska to California, and across much of North America. However, don’t mistake this beauty for a meal—Cryptoporus volvatus is inedible. But it’s certainly a wonder of nature with its cryptic, beetle-assisted life cycle. 🌳💫

🔎 Identification

🍄 Fruiting Body: Typically 0.39 to 2.76 inches (1 to 7 cm) across and 0.39 to 0.98 inches (1 to 2.5 cm) thick. At first, it's spherical, becoming convex and semicircular over time. Its smooth, shiny surface can range from chestnut-brown to buff-brown, occasionally with a pinkish hue at the attachment point. As it ages, the surface fades and loses its shine.

🧽 Pore Surface: The underside is covered by a 1–2.5 mm thick, whitish veil-like tissue, a volva, which extends from the cap margin. It’s typically pale to dark brown with 3–5 circular pores per mm, and the tubes are 3–5 mm deep.

🥩 Flesh: The flesh starts as white but turns pale brownish with age or drying, and has a corky texture.

🦠 Spore Print: The spore print is pinkish-buff, and the spores are elongated-elliptical, measuring 8-10 x 3.5-5 µm. The spores are smooth and hyaline to dull golden in KOH.

🌍 Habitat and Ecology: Found on dead conifers—both standing and fallen—often in areas affected by fire, insects, or disease. It’s typically observed within a year or so of the tree's death. Widely distributed across North America, as well as reported in South America and eastern Asia. This fungus plays an essential ecological role, typically being one of the first wood-rotting fungi to appear after a tree dies, often within a year or two, and contributing to a soft, grayish-brown rot in the outer sapwood. Look for it during summer and fall, or over winter in warmer climates. 🌿🔥

⚠️ Edibility: Inedible and too tough for the table, so enjoy this fascinating fungus for its unique ecological role rather than as a culinary find!

🔬 Microscopic Features: Spores are smooth and elongated, with a dull golden color in KOH. The hyphal system is trimitic, and cystidia are hyaline in KOH. The basidia are clavate and four-sterigmate.

📜 Synonyms

• Cryptoporus volvatus (Peck) Shear

• Cryptoporus volvatus var. pleurostoma (Patouillard) Saccardo (1912)

• Cryptoporus volvatus var. torreyi (W.R.Gerard) Shear

• Fomes volvatus (Peck) Cooke (1885)

• Fomes volvatus var. helix Hennings (1898)

• Fomes volvatus var. obvolutus (Berkeley & Cooke) Saccardo (1888)

• Fomes volvatus var. pleurostoma (Pat.) Sacc. & Traverso

• Fomes volvatus var. torreyi (W.R.Gerard) Sacc.

• Polyporus inflatus Ellis & I.C. Martindale (1884)

• Polyporus obvolutus Berkeley & Cooke (1878)

• Polyporus volvatus Peck (1875)

• Polyporus volvatus var. helix (Hennings) Murrill (1908)

• Polyporus volvatus var. obvolutus (Berkeley & Cooke) Peck (1880)

• Polyporus volvatus W.R.Gerard

• Scindalma volvatum (Peck) Kuntze (1898)

• Ungulina volvata (Peck) Pat.

• Ungulina volvata var. pleurostoma Patouillard (1907)

Photo sources:

Photo 1 - Author: Alan Rockefeller (CC BY-SA 4.0)

Photo 2 - Author: Madeleine Claire (CC BY 4.0)

Photo 3 - Author: Hilary Rose Dawson (CC BY 4.0)

Photo 4 - Author: Tyler Hacking (CC BY 4.0)