Danny’s DNA Discoveries – Stereaceae of the PNW
abundant common uncommon rare - colour codes match my Pictorial Key and are my opinions and probably reflect my bias of living in W WA. Rare species may be locally common in certain places at certain times.
"Crust fungi" are the hardest shape of fungi to identify, as just about every branch of the fungal tree of life started out with species that were crust-like, one of the most primitive forms (just like many branches eventually evolved a truffle-like form, one of the more advanced forms). That makes it extremely difficult to know anything about the genetic placement of crusts just by looking at them. Microscopy is often essential.
Stereum - click to expand
The orange colouration rescues these from obscurity, as does the fact that they usually project away from the surface and are not often fully resupinate. When scratched, they may stain/bleed red or yellow. The species are best separated microscopically, but can often be reliably identified by comparing how much they attach to the wood (single point, versus a line versus mostly resupinate), how bright or dull the orange colouration is on the underneath and whether or not it stains/bleeds yellow, red or neither when scratched.
Most collections of Stereum are called this, because this abundant species is the only one that most people know. It is mostly projecting from the wood, but broadly attached. The underside is bright orange, and the fruitbody is usually 1-2 mm thick. Like most, it is a hardwood species.
Western North American collections differ consistently from European sequences by the same single bp difference in ITS1 and the same 3 bp differences in ITS2 plus a large insertion of 8 bp. There may also be a few extra single indels. There is definitely some geographic isolation happening but I don't know that it's enough to consider ours a different species in need of a new name.
Stereum hirsutum © Julie Jones
Thinner than S. hirsutum (<0.5 mm), also brightly coloured and usually more wrinkled or complicated looking. It is probably common. We need local and European sequences to see if we have the real thing. We have eastern NA sequences that appear to be this species.
probable Stereum complicatum © James Hilliard
A common hairy capped species with a fringed edge, dull colours underneath and reportedly found on small pieces of wood. No DNA data yet to see if we really have this European species.
probable Stereum ochraceoflavum © Daniel Winkler
Stereum cf gausapatum
Mostly resupinate on oak, bright orange, bleeding red when scratched. Rare here. Our Vancouver Island sequence matches sequences from eastern North America (with a handful of alleles or dirty sections being the only differences), but we don't have European sequences yet to see if our species is the real thing.
Stereum cf rugosum
Pale brownish instead of bright orange. Also a resupinate red bleeder on various hardwoods, rumoured to occur here rarely. We need local collections to compare to European sequences to verify these reports.
Stereum cf sanguinolentum
A common, similar looking resupinate red bleeder, but dull tan-orange coloured on conifers. Eastern North American sequences match European sequences. We need local sequences to verify that ours is the same species too, but it probably is.
probable Stereum gausapatum, rugosum and sanguinolentum © A and O Ceska
Mostly a cap, attached to the wood at a single point only, dull orange underneath, staining yellow-orange when scratched. Uncommon on hardwoods.
Stereum ostrea - identical, but bleeding red or yellow turning red. So far, sequences of this rarely reported species have all turned out to be other species, according to a recent study, so we need sequences of supposed collections to test the theory that all of ours are really just Stereum subtomentosum that happens to stain more towards the orange-red end of the spectrum instead of yellow.
Stereum subtomentosum © Danny Miller
Stereum atrorubrum - described from BC but only known from the 1890 type, so we really don't know what it is. I'm curious.
Summary of Future Studies Needed - click to expand
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