Domain: Eukarya
Kingdom: Fungi
Phylum: Basidiomycota
Class: Agaricomycetes
Order: Polyporales
Family: Polyporaceae

Like a small puffball growing on a conifer trurnk Kuo² Almost always has a hole on the lower surface. Ginns¹

Cap: 1–4 cm wide¹ 1.5-8.5 cm wide², brown when fresh (spring), fading to white when old (by autumn), round to hoof-shaped, with a leathery membrane covering the pore layer except for a ~ 5 mm diameter hole bored by beetles next to the bark at the bottom. Attached to the bark by a hyphal cord emerging from the beetle tunnel.
Pore surface: pale brown fading to white, covered with a thick white to yellow membraneous veil that opens at maturity
Pore shape: circular, 3-5 per mm
Spores: pinkish, 8-12 × 3-5μm¹, 9-16 × 3-5 μm², cylindric, smooth, hyaline, inamyloid.
Hyphal system trimitic. Generative hyphae 3–7 μm diameter with clamp connections, inflated at branches to 15 μm; skeletal hyphae 2.5–8.0 μm diameter, binding hyphae 1.5–2.5 μm diameter; cystidia lacking; cystidioles fusoid, 20–28 × 5–7 μm; basidia clavate, 24–27 × 9–11 μm, four sterigmate; basidiospores 8–12 × 3–5 μm, cylindrical, walls hyaline, thin, smooth, neither amyloid nor dextrinoid.¹

North American and East Asia³; Western North America.¹ throughout North America.²

Conifers that died in the previous year.² Fruits annually in May-September on conifers, scattered or in groups, typically >= 10/trunk.^{1 2}

Cryptoporus sinensis has smaller spores (7.5-10 × 4.5μm) and is so far (2000) known from only central and southern China.³

Causes a soft grayish brown rot towards the outside of sapwood.^{1 2}

Since the dispersal of the spores usually involves the employment of wood boring beetles, C. volvatus can be used as an indicator for bark beetle kill on Douglas firs.

The fruiting body to this mushroom is very tough and so it is not edible.²

Decoction used in localities in China to wean infants from breast milk or as anti-inflammatory for asthma or bronchitis.³

¹ Ginns, J. 2017, Polypores of British Columbia. Prov. B.C. Tech. Rep. 104. https://www.for.gov.bc.ca/hfd/pubs/Docs/Tr/TR104.htm

² Kuo, M. (2005, March). Cryptoporus volvatus. Retrieved from the MushroomExpert.Com Web site: href=http://www.mushroomexpert.com/cryptoporus_volvatus.html

³ Wu, S.H.; Zang, M. 2000. Cryptoporus sinensis sp. nov., a new polypore found in China. Mycotaxon. 74(2):415-422

⁴ Index Fungorum Record 185937

⁵ Mycobank Record #185937

Notes: The opening or hole on the lower surface of each basidioma is a distinctive field character. Beetles, perhaps attracted by odour, carry basidiospores to recently dead or dying trees and construct a brood tunnel, within which the basidiospores germinate and the resultant mycelium permeates the sapwood.¹

“Cryptoporus” means “hidden pores.”
Also called the veiled polypore or the cryptic globe fungus. The veil is broken open by insects and small arthropods boring holes into the membrane. Peck originally named this as Polyporus volvatus