Several years ago a lightning-cause fired swept through an area along Lower Hat Creek (Shasta County CA). The fire was contained quickly and the area recovered rapidly. However the flames left many standing dead ponderosa pine trees. I noticed some fungi growing on the burned conifers but was unsure of what they were because the early growth looked nothing like the aged specimens.
Several weeks ago I went on a mushroom hike in Oregon. There were no mushrooms to be found – dry conditions? It was still a wonderful learning opportunity. Our leader, John, spent time talking to us about fungi and I asked about my unknown fungi. John sent me in the right direction. . . a veiled polypore (Cryptoporus volvatus).
Polypores produce their spores (reproductive body capable of producing a new plant, as a seed) on the insides of tubes rather than on gills, like the common mushrooms we are all familiar with. The veiled polypore sporocarp (fruiting body) begins as a globular, smooth surfaced, shiny orangish to chestnut-brown growth on conifers that were killed by fire, insects or other causes during the previous year. There is no stem.
As the sporocarp matures and ages it fades to a buff-brown and eventually to a whitish color. It looks like a puffball on the wood. The spore-producing pores form the upper part of the fungus.
A veil-like membrane (volva) covers the bottom of the spore-forming surface. The spores fall into a closed chamber (hollow interior with an upper wall of tubes) formed between the pore tissue and the membrane.
Spores are commonly dispersed by air currents. Yet the veiled polypore spores are trapped in a chamber and cannot fall free. What a clever mechanism the veiled polypore has for spreading its spores! As the spores mature and fall, a tiny “trap door” appears in the covering tissue. Wood-boring beetles searching for food enter the chamber through the trap door, feast on the mushrooms tubes and spores and then carry spores with them when they leave. As the beetle bores into new wood the veiled polypore germinates in a new place.
Veiled polypores, also know by the synonym Polyporus volvatus, are found on dead conifers and fallen logs throughout North America and are among the first wood-rotting fungi in the line of succession. They cause a grayish brown rot in the outer layer of sapwood. Rarely are veiled polypores found on a tree more than a year or two after it has died.
These photographs of veiled polypores on burned ponderosa pines (Pinus ponderosa) near Lower Hat Creek were taken over the course of a year. In the final picture the veil is removed from a dried polypore and the pores are visible.