Technical Description:The fungus Bridgeoporus (=Oxyporus) nobilissimus (W.B. Cooke) Volk, Burdsall & Ammirati is a perennial polypore, endemic to Washington and Oregon, that produces large basidiomata on the root crowns and trunks of living trees, snags, and stumps. Synonyms for basidiomata are fruiting bodies, sporocarps, or conks.
The polypore initially was named Oxyporus nobilissimus by W.B. Cooke (1949), but Burdsall et al. (1996) reclassified it as Bridgeoporus nobilissimus because species of Oxysporus have true cystidia arising from the subhymenium (fertile spore-producing surface) whereas B. nobilissimus has pseudocystidia (Redberg et al. 2003).
The fruiting body is characterized by a fibrous pileal surface with cracks and crevices from which vascular plants (e.g., Oxalis sp. and pteridophytes) and bryophytes often grow epiphytically (Redberg et al. 2003). The pileal surface is covered with a dense mat of white mycelial fibers in young basidiomata (fruiting bodies), often somewhat agglutinated (adhering like gluten or glue) at the tips, which become darker with age, reaching several mm in length. These fibers often are green, due to epimycotic associations with several species of algae, including Coccomyxa sp. and Charicium species (Burdsall et al. 1996). B. nobilissimus lacks clamp connections at the septa and has a monomitic hyphal system with pseudocystidia arising from the trama (hymenial tissue). The spores are 5.5-6.5 x 3.5-4.5 µm, broadly ovoid, hyaline, smooth, thin-walled, and inamyloid. The round pores are stratified with a layer of sterile tissue 2-3 mm thick between successive annual pore layers.
Perennial sporocarps (conks) can attain a weight of 130 kg (Burdsall et al. 1996) with the largest recorded conk 75 cm x 101 cm x 51 cm in size. This massive polypore often hosts epiphytic associations with algae, lichens, and mosses (Burdsall et al. 1996, Hibler and O’Dell 1998, Redberg et al. 2003, Cowden 2002). Due to its large size, fuzzy, pileal surface, and perennial persistence, B. nobilissimus is easily detected in the field (Hibler and O’Dell 1998, Cowden 2002).
Hibler and O’Dell (1997) described three general shapes for the fruiting bodies of B. nobilissimus, depending largely on their location on the host: (a) hoof-shaped and shelf-like conks found on the sides of hosts, (b) short, oblong-topped conks with tapering pore surfaces found on the main roots of the host, and (c) centrally substipitate (conical) conks located on the tops of stumps. Cowden (2002) expanded the descriptive morphology to four shapes: (a) shelved, (b) conical, (c) “button”/round, and (d) vertical. Of the conks observed in her study, 77% (n=62) of the 81 were shelved, 10% (n=8) conical, 11% (n=9) round, and 2% (n=2) vertical. Forty-five of the 60 dominant conks were shelved. Shelved conks were usually large and had algal growth and litterfall accumulation on the upper (pileal) surface of the sporocarp, and were found on trees, snags, and stumps. Seven dominant conks were conical. These conks only fruited on top of stumps and had algal growth and litterfall on the upper (pileal) surface of the sporocarp. Conical conks were characterized by a long stem, observed protruding from deep within the stump center. Six dominant rounded conks were observed, characterized as small conks with an active pileal surface but not acting as a secondary host to algae or mosses. These conks did not appear to have an active hymenium (fertile surface). Vertical conks were very rare, observed fruiting on only two stump hosts in Oregon. Characterized by a vertical growth pattern from the stump top downward, vertical conks were creamy beige in color and had no algal growth or litter present. To Cowden’s list can be added a fifth descriptive conk shape or type, dead, in which the conk displays visible signs of deterioration/decline (T. Fennell, pers. comm., 2007). Recognizing conks in a deteriorated state is equally important when attempting to determine the presence of B. nobilissimus within a survey area. See photos for comparison of conk shapes.
Life History:The life history of B. nobilissimus is poorly understood.The hyphae/mycelia (vegetative stage) of a polypore may grow for a considerable span of time as the fungus accumulates resources to form its large fruiting bodies (Gilbertson and Ryvarden 1986). Like most macrofungi, B. nobilissimus is only identifiable in its reproductive stage (i.e., by its fruiting body). Hyphae/mycelia in wood or soil can only be identified using molecular techniques:species-specific polymerase chain reaction (PCR) primers (Redberg et al. 2003).
B. nobilissimus consistently has been associated with brown rot (a type of wood decay)(Burdsall et al. 1996), in which lignin is not appreciably degraded (Boddy and Watkinson 1995); however, the true rot characteristics of B. nobilissimus remain unresolved because efforts to culture it have been unsuccessful to date (Redberg et al. 2003). B. nobilissimus might cause a white rot and the brown rot observed in the association may be due to another species, possibly Fomitopsis (Redberg et al. 2003). B. nobilissimus is probably a brown or white rot, but whether it is a saprobe, pathogen, or possibly a commensal or mutualistic endophyte to noble fir is not known (Redberg et al. 2003). Fungi can switch lifestyles depending on host genotype and environmental conditions, so it is possible for B. nobilissimus to be all of the above at different times (R. Rodriguez, pers. communication, 2007). Also, there may be other biological associations besides the one between the fungus and its tree host that are important: e.g., bacteria may be symbiotic with the fungus or involved in its life history, nutrient supplementation may come from algae associated with conks, or the fungus may be mycorrhizal (R. Rodriguez, pers. communication, 2007). It is unclear what drives B. nobilissimus to establish and produce conks.
Range, Distribution, and Abundance:Olympic Mountains and western Cascade Range from northwest Washington (Olympic and Mt. Baker-Snoqualmie National Forests) to central western Oregon (Willamette National Forest) at elevations of 300-1,300 meters (1,000 to 4,300 feet) with one known site in the Oregon Coast Range (Mary’s Peak, Siuslaw National Forest) (Redberg et al. 2003, Cowden 2002). As of April 2007, 104 sites (locations) of B. nobilissimus are known in the Pacific Northwest, the majority of them on the Cascade Resource Area of the BLM Salem District in Clackamas, Marion, and Linn counties, which appears to be the “epicenter” of the species’ distribution.
Habitat Associations:Fruiting bodies occur on large, dying and dead noble fir and Pacific silver fir in late-successional old-growth forests and on remnant stumps and snags in young and mature second-growth forests in the Pacific silver fir and western hemlock zones in western Washington and Oregon (Cowden 2002, Redberg et al. 2003). Known hosts for B. nobilissimus are limited to noble fir and Pacific silver fir, but potentially may include other true firs (Abies grandis, Abies magnifica var. shastensis, Abies concolor) and western hemlock (Cowden 2002; Redberg et al. 2003; J. Trappe, pers. communication, 2007; D. Shaw, pers. communication, 2007). Fruiting bodies have been found, for the most part, on large stumps but occasionally on snags and live trees too.
The species has been reported most commonly on large-diameter (at least 1 m) Abies procera (noble fir), infrequently on Abies amabilis (Pacific silver fir), and possibly on Tsuga heterophylla (western hemlock), typically fruiting within 1 m of the ground (Redberg et al 2003). Unlike many polypores, B. nobilissimus has not been observed on downed logs or any form of dead wood that lacked roots or some connection to a root system (Cowden 2002). Fruiting bodies were reported growing from the upturned root system/crown of one windthrown tree with intact roots (J. Ammirati, pers. communication, 1997, reported in Redberg et al. 2003). On the Mt. Hood National Forest, a once vital conk died within several years after its host was uprooted by a fallen tree (Cowden 2002). The fact that B. nobilissimus is only known to fruit on hosts connected to a root system is evidence that root systems are a quintessential part of the organism’s persistence, implying that B. nobilissimus is similar ecologically to butt rots such as annosus root rot (Heterobasidion annosum) and dyer’s polypore (Phaeolus schweinitzii) (Cowden 2002).
Threats:(1) Extirpation of known and unknown sites by logging, fire, or other disturbance. (2) Forest practices that result in loss of large-diameter noble fir and Pacific silver fir trees and biological legacy structures (large-diameter stumps and snags) in managed forests. Many sporocarps of B. nobilissimus have been observed in various states of decline (Hibler and O’Dell 1997; M.Cowden, pers. communication, 2002; T. Fennell, pers. communication, 2007; A. Smith, pers. communication, 2007). The health and population dynamics of B. nobilissimus and its sporocarps across the species’ range are unknown. Lack of habitat for the species (i.e., large noble fir and Pacific silver fir trees and biological legacy structures) will most likely limit conservation efforts.
Conservation Considerations:Conserve large noble and Pacific silver fir trees, snags, and stumps in managed forests. Manage young stands with a significant component of noble fir to promote large-diameter trees that could support B. nobilissimus in the future. B. nobilissimus was placed on the Oregon Natural Heritage Program’s endangered species list in 1995, making it one of the first fungi to be listed by any private or public agency in the United States. The Forest Ecosystem Management Assessment Team (FEMAT) Report 1993 (p. IV 86-89) stated the need for collecting information on old-growth associated fungi of the Pacific Northwest. It specifically noted that a long-term study of B. nobilissimus should be initiated and include information on distance and effectiveness of spore dispersal. Currently, B. nobilissimus is on the Regional Forester’s Sensitive Species List (Region 6, Pacific Northwest) and is Sensitive under the BLM Special Status Species program.
Further research on B. nobilissimus is needed to address basic questions about its biology and ecology, about which we still know very little. To complement ongoing field surveys for B. nobilissimus conks, the U.S. Forest Service (Region 6) and Bureau of Land Management (WA and OR) are collaborating with researchers to explore and expand the possibilities of detecting the presence of B. nobilissimus in forests through taking wood and soil samples in the field and then analyzing them back in the lab using molecular techniques (PCR primers) to detect the B. nobilissimus genome.
Bridgeoporus is a fungal genus in the family Polyporaceae. A monotypic genus, it contains the single polypore species Bridgeoporus nobilissimus, first described to science in 1949. Commonly known both as the noble polypore and the fuzzy Sandozi, this fungus produces large fruit bodies (or conks) that have been found to weigh up to 130 kilograms (290 lb). The upper surface of the fruit body has a fuzzy or fibrous texture that often supports the growth of algae, bryophytes, or vascular plants.
This species is found in the Pacific Northwest region of North America where it grows on large (at least 1 m diameter) specimens of noble fir (Abies procera), Pacific silver fir (Abies amabilis), or western hemlock (Tsuga heterophylla). Bridgeoporus nobilissimus causes a brown rot in its tree hosts. Genetic analysis shows that the fungus is more prevalent than fruit body distribution indicates.
Bridgeoporus nobilissimus was named for William Bridge Cooke, who originally described the species as Oxyporus nobilissimus in 1949. The fungus was discovered in Clackamas County, Oregon, in 1943 by brothers Ali and Fred Sandoz. Foresters called the species Fomes fuzzii-sandozii, referring to the collectors and the fuzzy surface texture of the conk. Several collections were made in Oregon and Washington in subsequent years. A large specimen was collected in Lewis County, Washington in 1946 that weighed about 300 pounds (140 kg) and measured 56 inches (140 cm) by 37 inches (94 cm). Cooke learned of the fungus in 1948 while visiting Daniel Elliot Stuntz, who kept one of the large fruit bodies that he and Alexander H. Smith had previously collected in Mount Rainier National Park. This fruit body served as the type collection.[2]
Species of genus Oxyporus cause white rot in their host trees. Cooke placed the fungus in this genus by despite not knowing definitively what type of rot it caused; he considered it to be closely related to Oxyporus populinus.[2] In 1955, polypore specialist Josiah Lincoln Lowe transferred O. nobilissimus to Fomes,[3] before the concept of this genus was narrowed. In 1996 the new genus Bridgeoporus was circumscribed by Harold Burdsall, Tom Volk and Joseph Ammirati to accommodate this species, in order to rectify incompatibilities with placements in Fomes and Oxyporus. In particular, genus Oxyporus features true cystidia arising from the subhymenium (the supportive hyphae underlying the hymenium), whereas B. nobilissimus has pseudocystidia (sterile structures arising deep in the subhymenium and protruding into the hymenium).[4]
Phylogenetic analyses of mitochondrial small-subunit rDNA sequences suggests that B. nobilissimus, which belongs in the hymenochaetoid clade, is closely related to the genera Oxyporus and Schizopora.[5] The hymenochaetoid clade includes wood-decaying species previously classified variously in the families Corticiaceae, Polyporaceae and Stereaceae.[6]
Bridgeoporus nobilissimus has perennial, imbricate, sessile fruit bodies that measure 30–140 cm (12–55 in) by 25–95 cm (9+7⁄8–37+3⁄8 in) by 30–100 cm (12–39 in).[5] From 1966 to 1990, this species was designated the largest pore fungus in the Guinness Book of World Records.[7] Three fruit body shapes are associated with the fungus, depending largely on the location of the fruiting on the host tree. Hoof-shaped and shelf-like conks are located on the sides of hosts; short, oblong-topped conks with tapering pore surfaces occur on the main roots of the host; and centrally substipitate (conical) conks are found on the tops of stumps.[5] The cap surface of young fruit bodies are covered with a dense mat of white mycelial fibers (up to several millimeters long) that in age darken in color and often become stuck together at their tips. Although the surface is typically brown or darker, it may appear green due to epiphytic associations with algae such as Coccomyxa or Charicium species.[5] Bryophytes or sometimes vascular plants grow on the upper surface of the conk. The texture of the fruit body is fibrous; it is rubbery and tough when fresh, but becomes hard and brittle when it is dry. The pores on the underside of the fruit body are round, approximately 2 per mm. The tubes comprising the pores becomes stratified, layering over each other with each successive year of growth. There is a 2–3 mm-thick layer of sterile tissue between pore layers, and mature tube layers are 2–7 mm long.[4]
Microscopically, B. nobilissimus is characterized by hyphae with a septum, pseudocystidia originating from the trama, closely appressed hyphae in bundles (fascicles) on the upper surface of the fruit body. The spore-bearing cells, the basidia, are 12–18 by 4–10 µm in size, pear-shaped, and four-spored. The roughly ovoid basidiospores are 5.5–6.5 by 3.5–4.5 µm, hyaline, smooth, and have thin walls.[4]
The fruit bodies (also called conks) of Bridgeoporus are found singly or sometimes in overlapping layers on old trees (1–2 m (3+1⁄4–6+7⁄12 ft) diameter at breast height) of noble fir (Abies procera), and more rarely Pacific silver fir (Abies amabilis) or western hemlock (Tsuga heterophylla).[8] It has also been recorded growing on a snag of redwood.[9] Other tree species often found in B. nobilissimus habitats include Douglas-fir (Pseudotsuga menziesii), western redcedar (Thuja plicata), and western hemlock. Common shrubs at these sites include salal (Gaultheria shallon), Sitka alder (Alnus sinuata), rhododendron (Rhododendron macrophyllum), and Alaska blueberry (Vaccinium ovalifolium).[10] The use of molecular genetic techniques has demonstrated that the fungus also lives in Douglas fir, western hemlock, and western redcedar, although its fruit bodies have not been seen on these hosts.[9]
The fungus has been found in the Cascade Range in Washington and Oregon, the Coast Range on the Olympic Peninsula in Washington, and in Redwood National Park in northern California.[9] Specimens have been found at elevations of 1,000–4,000 feet (300–1,220 m).[8] Because the fungus feeds on both dead and living wood,[10] it is both parasitic and saprophytic.[4] B. nobilissimus fruit bodies do not occur on fallen logs or other forms of dead wood lacking roots or some connection to a root system. Conks have been found growing on the still-living roots of an upturned, windthrown tree, while a once-living conk died within several years after the host tree was uprooted by a fallen tree.[11]
Threats to Bridgeoporus nobilissimus include extirpation of known and unknown habitats by logging, fire, or other disturbances, and forestry practices that lead to the loss of large-diameter Abies procera and Abies amabilis trees and large-diameter stumps and snags in managed forests.[11] Due to the scarcity of its mature tree hosts, B. nobilissimus was listed in 1995 as an endangered species by the Oregon Natural Heritage Program, making it the first of the fungi to be listed as endangered by any private or public agency in the United States.[12][13] It is the sole fungus in category A of the survey and management guidelines for fungi under the Northwest Forest Plan, meaning pre-disturbance surveys and site management are needed before developing areas known to harbor the fungus.[14] There were 13 known sites with the fungus before 1998; extensive surveying in the Pacific Northwest increased this number to 103 sites by 2006.[15] Although it is infrequently observed, the fungus is more abundant than fruit body appearance indicates. Using genetic markers to detect the fungus mycelium in hosts, researchers found that B. nobilissimus was present at low to moderate levels and widespread in forest stands containing at least a single visible fruit body. It was detected in trees of all sizes, and in species not previously thought to harbor the fungus. B. nobilissimus may require decades of mycelial growth in its host before fruit body production is initiated. The fungus has not been successfully grown in vitro despite several attempts.[9]
Bridgeoporus is a fungal genus in the family Polyporaceae. A monotypic genus, it contains the single polypore species Bridgeoporus nobilissimus, first described to science in 1949. Commonly known both as the noble polypore and the fuzzy Sandozi, this fungus produces large fruit bodies (or conks) that have been found to weigh up to 130 kilograms (290 lb). The upper surface of the fruit body has a fuzzy or fibrous texture that often supports the growth of algae, bryophytes, or vascular plants.
This species is found in the Pacific Northwest region of North America where it grows on large (at least 1 m diameter) specimens of noble fir (Abies procera), Pacific silver fir (Abies amabilis), or western hemlock (Tsuga heterophylla). Bridgeoporus nobilissimus causes a brown rot in its tree hosts. Genetic analysis shows that the fungus is more prevalent than fruit body distribution indicates.
Bridgeoporus nobilissimus est une espèce de champignons basidiomycètes de la famille des Schizoporaceae. C'est un des rares taxons de champignons qui ait été évalué en danger critique par l'Union internationale pour la conservation de la nature.
Bridgeoporus nobilissimus est une espèce de champignons basidiomycètes de la famille des Schizoporaceae. C'est un des rares taxons de champignons qui ait été évalué en danger critique par l'Union internationale pour la conservation de la nature.
| fotkaraktär = inte tillämpbart | sporavtrycksfärg = }} Bridgeoporus nobilissimus je grzib[3], co go nojprzōd ôpisoł W.B. Cooke, a terŏźnõ nazwã doł mu T.J. Volk, Burds. & Ammirati 1996. Bridgeoporus nobilissimus nŏleży do zorty Bridgeoporus, klasy Agaricomycetes, grōmady Basidiomycota i krōlestwa grzibōw.[4][5] Żŏdne podgatōnki niy sōm wymianowane we Catalogue of Life.[4]
| fotkaraktär = inte tillämpbart | sporavtrycksfärg = }} Bridgeoporus nobilissimus je grzib, co go nojprzōd ôpisoł W.B. Cooke, a terŏźnõ nazwã doł mu T.J. Volk, Burds. & Ammirati 1996. Bridgeoporus nobilissimus nŏleży do zorty Bridgeoporus, klasy Agaricomycetes, grōmady Basidiomycota i krōlestwa grzibōw. Żŏdne podgatōnki niy sōm wymianowane we Catalogue of Life.
