Stereum sanguinolentum

Stereum sanguinolentum is a species of fungus in the Stereaceae family. A plant pathogen, it causes red heart rot, a red discoloration on conifers, particularly spruces or Douglas-firs. Fruit bodies are produced on dead wood, or sometimes on dead branches of living trees. They are a thin leathery crust of the wood surface. Fresh fruit bodies will bleed a red-colored juice if injured, reflected in the common names bleeding Stereum or the bleeding conifer parchment. It can be the host of the parasitic jelly fungus Tremella encephala. The species was first described scientifically by Albertini and Schweinitz in 1805 as Thelephora sanguinolenta. Other genera to which it has been transferred throughout its taxonomical history include Phlebomorpha, Auricularia, Merulius, and Haematostereum. The fungus is commonly known as the 'bleeding Stereum' or the 'bleeding conifer parchment'. The fruit body of Stereum sanguinolentum manifests itself as a thin (typically less than 1 mm thick) leathery crust on the surface of the host wood. Often, the upper edge is curled to form a narrow shelf (usually less than 10 mm thick). When present, these shelves are can be fused to or overlap neighboring shelves. The surface of the fruit body consists of a layer of fine felt-like hairs, sometimes pressed flat against the surface. The color ranges from beige to buff to dark brown in mature specimens; the margin are lighter-colored. Fresh fruit bodies that are injured exude a red juice, or will bruise a red color if touched. The fruit bodies dry to a greyish-brown color. The spores are ellipsoid to cylindrical, amyloid, and typically measure 7–10 by 3–4.5 µm. Stereum sanguinolentum can be parasitized by the jelly fungus Tremella encephala. Stereum sanguinolentum is a basidiomycete that causes both brown rot and white rot on conifers. The primary symptom is the red streaking discoloration. White rot basidomycete causes an extensive decay resulting from wounds, logging extractions; bark peeking, or branch pruning. Stereum sanguinolentum forms territorial clones while spreading by vegetative growths between spatially separated resource units; Armillaria spp, Heterobasidion annosum, Phellinus weirii, Inonotus tomentosus, and Phellinus noxius all work with Stereum sanguinolentum to attack the host. The combinations of these pathogens work together to form territorial clones that can cover up to several hectares and survive for hundreds of years while infecting trees. White rot causes a gradual decrease in cellulose as the decay continues to affect the tree. The white rot fungi consume the segments of cellulose that are released during the decay as quickly as they are produced. White rot is also known as “wound rot of spruce” and is when the spores create open wounds on the host. In Brown Rot, the cellulose is degraded. The rapid decrease in cellulose chain length implies that the catalyst that facilitates the depolymerization readily gains access to cellulose chains. Stereum sanguinolentum is an amphithallic basidiomycete. Monospore intrabasidiome pairings are always compatible when reproducing making it easy for the fungus to spread. The monobasidiospore and trama isolates are plurinucleate and bear clamp connections and are often dikaryotic. Basidiospores are heterokikaryotic indicating that they are amphithallic. The mycelia that spreads the fungi grow from the heterodikaryotic spores that originate from the basidiospores. Either mating between homokaryons originating from the monokaryotic basidiospores or by the parasexual process results in recombination.