When you think of a polypore, you normally wouldn’t first think of this species. You probably would start imagining a wood decomposing fungus, with pores on its underside, and a leathery, durable cap surface. But as you know, fungi don’t always look like the species they are closely related to. Twice already I have featured fungi that produce gills but are not closely related to the true Agarics. We see this trend over and over, showing how confusing this mycological realm really is. This organismal Kingdom has gone through more phylogenetic restructuring than any other facet of life. For hundreds of years, mycologists have jostled different families around the fungal phylogenetic tree based on morphological traits. In modern times, the use of genetic sequences is clarifying our missteps along the way, and are helping us build a detailed, sound picture of this diverse Kingdom that we know and love.
At first glance, this species looks like a puffball. If you take anything away from this blog, it should be the awareness to never judge a fungus by its fruiting body! On closer examination, this species actually fills the qualifications of a polypore. Only this polypore is completely veiled, hence its common name, the veiled polypore. Like an immature Amanita, this protective veil encases the reproductive tissues within. Eventually, one or two holes form on the underside of the veil, allowing millions of spores to billow out so the species life cycle can continue.
Cryptoporus volvatus fruits from the sapwood of conifer trees throughout the United States, Canada, and most of Asia. Some younger specimens of this species appear red orange, but many observations of this fungus show a more pale-yellow to white color. If you do happen to find the white variation of this fungus, you might confuse it with similar looking medium-small puffball species. However, once sliced open, the pore surface within the encased veil quite clearly indicates which species you stumbled across.
Before the ecology of this fungus was understood, the veil of this species seemed to help protect it against mycophagous insects. As our collective mycological knowledge increases, so does the descriptions of Earth’s forest floor inhabitants. In 1980, T. C. Harrington quantified the species spore release throughout the year and found that most spores were discharged in two of the three dryer months of the year, June and July. Thus, it was hypothesized that this veil protects the species from excess water loss. During these dryer months it is imperative that the species has enough water within its fruiting body so the actual spore can utilize the momentum from the Buller's droplet to break away from the basidium. With a veil covering its entire surface, it maintains enough water resources to release spores from basidia. Though an even closer look shows yet another ecological function.
This fungus is commonly used as an indicator species, signifying that pine beetles have successfully infiltrated coniferous trees. The next time you find this species, look for evidence of beetles around the fungus. Chances are, you will find tiny bore holes that penetrate to the inner sapwood, the substrate Cryptoporus volvatus specializes in. So, what’s going on here? Interestingly, this species actually harbors these wood-boring beetles. The veil maintains the temperature and moisture niche requirements of the beetles and also ensures that each beetle becomes completely covered in spores. Initially, I was perplexed by this veil, because clearly it impedes wind spore dispersal. Cryptoporus volvatus has evolved a more active approach to spore dispersal by using a beetle vector.
The veiled polypore, Cryptoporus volvatus has an incredible ecology, taking advantage of voracious, wide dispersing beetles. It is no surprise to me how many times beetles and other fungi have form long-lasting mutualistic relationships. They both require many of same conditions and in this specific case, utilize the same substrate for food. With such an overlap in niche requirements, these symbiotic relationships were bound to evolve. This unique polypore has a veil that combats desiccation in the dryer months, when it is most active. Additionally, this veil creates the perfect environment to house its spore disperser, species of wood-boring beetles.