Rhizina undulata

Last updated

Rhizina undulata
Rhizina undulata California.jpg
Scientific classification OOjs UI icon edit-ltr.svg
Domain: Eukaryota
Kingdom: Fungi
Division: Ascomycota
Class: Pezizomycetes
Order: Pezizales
Family: Rhizinaceae
Genus: Rhizina
Species:
R. undulata
Binomial name
Rhizina undulata
Fr. (1815) [1]
Synonyms [2]
  • Helvella inflata Schaeff. (1774)
  • Rhizina laevigataFr. (1815)
  • Rhizina praetexta Ehrenb. (1818)
  • Rhizina laevigata var. praetexta(Ehrenb.) Pers. (1822)
  • Rhizina inflata(Schaeff.) Quél. (1886)
  • Rhizina inflata var. rhizophora Massee

Rhizina undulata, commonly known as the doughnut fungus or the pine firefungus, is a species of fungus in the family Rhizinaceae. The fruit bodies of the fungus are dark purple brown with a bright yellow margin, crust-like and attached to the growing surface by numerous root-like yellow rhizoids. R. undulata has a cosmopolitan distribution, and commonly occurs on clearings or burned areas throughout central and northern Europe, North America, northern Asia, and southern Africa. It is parasitic on conifer seedlings, and has caused considerable damage to tree plantations worldwide.

Contents

Taxonomy

The fungus was first described in 1774 as Helvella inflata by the German polymath Jacob Christian Schäffer. [3] It acquired its current name in 1815 by virtue of its publication in Elias Magnus Fries's Observationes Mycologicae. [2]

The specific epithet undulata means "wavy" or "undulating". Common names that have been used to refer to the species include "crust-like cup", "pine-fire cushion", [4] "doughnut fungus", [5] and "pine firefungus". [6]

Description

Fruit bodies (apothecia), which may be up to 6 cm (2.4 in) wide, are flat, with irregular lobes, and are attached to the growing surface on the entire lower side by numerous whitish to yellowish rhizomorphs. The hymenium is dark purple brown to blackish, while the margin is a cream color(like the underside), and wavy and irregular. [7] When moist, the surface is sticky. [8] The fruit body has a leathery texture when old. [9] In very young fruit bodies, the surface is white; the brown color initially appears in the center and expands rapidly thereafter. [8] Later in the growing season, several of these apothecia may clump together and form irregularly-shaped structures up to 25 cm wide. [10] They will lose their cream-colored ring and become black. These are the resting structures that will allow the fungus to survive unfavorable conditions until another fire occurs and the ascospores germinate.

The spores of Rhizina undulata are fusiform (fuse-shaped), apiculate, minutely verricose at maturity, with one or two oil drops, and have dimensions of 30–40 by 8–11  µm. [7] The asci are roughly cylindrical, and 250–280 by 14–18 µm. [11] Like most other Pezizales, the asci open at maturity by means of an apical, lid-like flap of tissue termed an operculum. The paraphyses are slightly club-shaped, tips encrusted with tubular setae, thin-walled, brown, aseptate and parallel-sided, tapering to a blunt point, and are 7–11 µm wide. [7]

Similar species

Discina ancilis is a lookalike Discina perlata 95195.jpg
Discina ancilis is a lookalike

Disciotis venosa has an overall similar blistered appearance, but can be distinguished by its distinct bleach-like odor. Discina ancilis bears a general resemblance to Rhizina undulata, but its fruit bodies lack rhizoids on their undersurface, and are attached to the substrate at a central point. [12]

Symptoms and Signs

One of the main symptoms of the seedlings are that they appear stressed. The needles will be necrotic, and they can appear girdled at or below the soil line. Leader growth will also be stunted. The roots will be covered in lesions and white to yellow mycelium. Symptoms can also appear on mature trees, and may include extensive cone production, reduced shoot growth, a significant amount of resin production from the lower part of the stem, and chlorotic and necrotic needles. [10] Fruiting structures will be very distinct, as they can be up to 6 cm in diameter and are chestnut brown with brain-like lobes and fissures. The presence of these fruiting structures, as well as their proximity to the trees, can be critical signs in diagnosis of Rhizina root disease. Other contributing factors are the proximity of the fire sites as well as the mycelium and the lesions present on the roots. [10] The signs and symptoms are most commonly seen in the late summer and fall in wet years.

Habitat and distribution

This is a widespread fungus that grows on burned soil or conifer debris. The spores are activated by the heat of the fire, which is why the disease is present in burned soil. This is because the fire breaks the spore dormancy and also creates a competitive advantage and allows the fungus to thrive. It prefers growing in acidic soil. [13] [14] Although it is regarded as a saprobic species, it can also attack conifers of varying age parasitically. [15] Its parasitic nature was recognized by scientists in the late 1800s and early 1900s, [16] [17] in particular, through several studies by German forestry scientist and mycologist Robert Hartig. He determined that the fungus can cause the death of four-year-old seedlings of several conifers, including European silver fir ( Abies alba ), eastern white pine ( Pinus strobus ), European larch ( Larix decidua ), Sitka spruce ( Picea sitchensis ), mountain hemlock ( Tsuga mertensiana ), Douglas fir Pseudotsuga menziesii , and sweet chestnut ( Castanea vesca ). [18] [19] [20] [21] Later research determined that the fungus also attacks conifers between 15 and 60 years old. [22] [23]

The roots of seedling attacked by R. undulata are matted together with a white mycelium that penetrates all parts of the cortical and bast tissues. Hartig grew the fungus in culture, and was able to follow the growth of the mycelium using light microscopy. He wrote: [20]

[the mycelium] grows between the cells of the parenchymatous tissues, while in the soft bast its progress is partly intercullular and partly intracellular, the sieve-tubes being frequently packed full of a dense filamentous mycelium. In the process of time the mycelium kills the tissues of the cortex and soft bast, whose elements become brown and completely dismembered ... The development is so luxuriant that it forms, in certain places, a pseudo-parenchymatous fungus-tissue, consisting of vesicular swollen cells. This however is speedily destroyed as soon as the tissues between the wood and periderm become almost completely destroyed.

The mycelial strands surrounding the diseased roots are continuous with the rhizoid strands that originate from the fruit body underside and attach it to the substrate. [17]

Rhizina undulata attack in recently established conifer plantations in areas where slash burning after clearcutting has been performed is a well-known phenomenon. Because the optimum temperature for spore germination is high (35–45 °C (95–113 °F)), the spores may lie dormant in soil for two years. [24] As a result of these fires, the underlying soil is heated so that suitable conditions are created for the germination of ascospores. The use of hot asphalt (110–130 °C (230–266 °F)) for paving new roads has also been observed to cause the same deleterious effect on neighboring conifers. [25] Rhizina undulata has been recorded in northern Asia, Europe, and North America. It has been introduced into southern Africa. [12]

Rhizina undulata is a homothallic fungus, and so it can produce fruit bodies without mating with another individual. [26] Fruit bodies can occur prolifically in favorable habitats. In one recorded instance there were over 300 fruit bodies found within a radius of 6–7 m (20–23 ft) of a single pine stump. [27] Some studies have suggested that the fungus spreads radially from a single starting point, so that the fruit bodies appear in wider circles in successive years (similar to growth observed in a fairy ring), [28] [29] but other studies have not noticed this phenomenon. [22] [23] The spread of the fungus stops four to seven years after the initial infection. [30]

Management

Preventing the disease from happening is easier than trying to cure it once it has started. Avoiding burning after clearfelling an area is one way to help prevent the spread of the disease. One of the main ways to prevent the disease is to delay planting of trees for 1.5 to 2 years after a forest fire or burning due to the fact that heat is what activates the spores.

Related Research Articles

<span class="mw-page-title-main">Ascomycota</span> Division or phylum of fungi

Ascomycota is a phylum of the kingdom Fungi that, together with the Basidiomycota, forms the subkingdom Dikarya. Its members are commonly known as the sac fungi or ascomycetes. It is the largest phylum of Fungi, with over 64,000 species. The defining feature of this fungal group is the "ascus", a microscopic sexual structure in which nonmotile spores, called ascospores, are formed. However, some species of the Ascomycota are asexual, meaning that they do not have a sexual cycle and thus do not form asci or ascospores. Familiar examples of sac fungi include morels, truffles, brewers' and bakers' yeast, dead man's fingers, and cup fungi. The fungal symbionts in the majority of lichens such as Cladonia belong to the Ascomycota.

<i>Armillaria</i> Genus of fungi

Armillaria is a genus of fungi that includes the A. mellea species known as honey fungi that live on trees and woody shrubs. It includes about 10 species formerly categorized summarily as A. mellea. Armillarias are long-lived and form the largest living fungi in the world. The largest known organism covers more than 3.4 square miles (8.8 km2) in Oregon's Malheur National Forest and is estimated to be 2,500 years old. Some species of Armillaria display bioluminescence, resulting in foxfire.

<i>Armillaria mellea</i> Species of fungus

Armillaria mellea, commonly known as honey fungus, is a edible basidiomycete fungus in the genus Armillaria. It is a plant pathogen and part of a cryptic species complex of closely related and morphologically similar species. It causes Armillaria root rot in many plant species and produces mushrooms around the base of trees it has infected. The symptoms of infection appear in the crowns of infected trees as discoloured foliage, reduced growth, dieback of the branches and death. The mushrooms are edible but some people may be intolerant to them. This species is capable of producing light via bioluminescence in its mycelium.

<i>Morchella esculenta</i> Species of fungus

Morchella esculenta is a species of fungus in the family Morchellaceae of the Ascomycota. It is one of the most readily recognized of all the edible mushrooms and highly sought after. Each fruit body begins as a tightly compressed, grayish sponge with lighter ridges, and expands to form a large yellowish sponge with large pits and ridges raised on a large white stem. The pitted yellow-brown caps measure 2–7 centimetres broad by 2–10 cm (1–4 in) tall, and are fused to the stem at its lower margin, forming a continuous hollow. The pits are rounded and irregularly arranged. The hollow stem is typically 2–9 cm long by 2–5 cm (1–2 in) thick, and white to yellow. The fungus fruits under hardwoods and conifers during a short period in the spring, depending on the weather, and is also associated with old orchards, woods and disturbed grounds.

<i>Hericium erinaceus</i> Edible mushroom

Hericium erinaceus is an edible mushroom belonging to the tooth fungus group. Native to North America, Europe, and Asia, it can be identified by its long spines, occurrence on hardwoods, and tendency to grow a single clump of dangling spines. The fruit bodies can be harvested for culinary use.

<i>Rhizoctonia solani</i> Species of fungus

Rhizoctonia solani is a species of fungus in the order Cantharellales. Basidiocarps are thin, effused, and web-like, but the fungus is more typically encountered in its anamorphic state, as hyphae and sclerotia. The name Rhizoctonia solani is currently applied to a complex of related species that await further research. In its wide sense, Rhizoctonia solani is a facultative plant pathogen with a wide host range and worldwide distribution. It causes various plant diseases such as root rot, damping off, and wire stem. It can also form mycorrhizal associations with orchids.

<i>Sclerotinia sclerotiorum</i> Species of fungus

Sclerotinia sclerotiorum is a plant pathogenic fungus and can cause a disease called white mold if conditions are conducive. S. sclerotiorum can also be known as cottony rot, watery soft rot, stem rot, drop, crown rot and blossom blight. A key characteristic of this pathogen is its ability to produce black resting structures known as sclerotia and white fuzzy growths of mycelium on the plant it infects. These sclerotia give rise to a fruiting body in the spring that produces spores in a sac which is why fungi in this class are called sac fungi (Ascomycota). This pathogen can occur on many continents and has a wide host range of plants. When S. sclerotiorum is onset in the field by favorable environmental conditions, losses can be great and control measures should be considered.

<i>Heterobasidion annosum</i> Species of fungus

Heterobasidion annosum is a basidiomycete fungus in the family Bondarzewiaceae. It is considered to be the most economically important forest pathogen in the Northern Hemisphere. Heterobasidion annosum is widespread in forests in the United States and is responsible for the loss of one billion U.S. dollars annually. This fungus has been known by many different names. First described by Fries in 1821, it was known by the name Polyporus annosum. Later, it was found to be linked to conifer disease by Robert Hartig in 1874, and was renamed Fomes annosus by H. Karsten. Its current name of Heterobasidion annosum was given by Brefeld in 1888. Heterobasidion annosum causes one of the most destructive diseases of conifers. The disease caused by the fungus is named annosus root rot.

<span class="mw-page-title-main">Hydnellum peckii</span> Species of fungus

Hydnellum peckii is a fungus in the genus Hydnellum of the family Bankeraceae. It is a hydnoid species, producing spores on the surface of vertical spines or tooth-like projections that hang from the undersurface of the fruit bodies. It is found in North America, Europe, and was recently discovered in Iran (2008) and Korea (2010). Hydnellum peckii is a mycorrhizal species, and forms mutually beneficial relationships with a variety of coniferous trees, growing on the ground singly, scattered, or in fused masses.

<i>Geopyxis carbonaria</i> Species of fungus

Geopyxis carbonaria is a species of fungus in the genus Geopyxis, family Pyronemataceae. First described to science in 1805, and given its current name in 1889, the species is commonly known as the charcoal loving elf-cup, dwarf acorn cup, stalked bonfire cup, or pixie cup. The small, goblet-shaped fruitbodies of the fungus are reddish-brown with a whitish fringe and measure up to 2 cm across. They have a short, tapered stalk. Fruitbodies are commonly found on soil where brush has recently been burned, sometimes in great numbers. The fungus is distributed throughout many temperate regions of the Northern Hemisphere. It is found in Europe, Turkey, and North America. Although it is primarily a saprotrophic species, feeding on the decomposing organic matter remaining after a fire, it also forms biotrophic associations with the roots of Norway spruce.

<i>Urnula craterium</i> Species of fungus

Urnula craterium is a species of cup fungus in the family Sarcosomataceae. It is parasitic on oak and various other hardwood species; it is also saprobic, as the fruit bodies develop on dead wood after it has fallen to the ground. Appearing in early spring, its distinctive goblet-shaped and dark-colored fruit bodies have earned it the common names devil's urn and the gray urn. The distribution of U. craterium includes eastern North America, Europe, and Asia. It produces bioactive compounds that can inhibit the growth of other fungi. The asexual (imperfect), or conidial stage of U. craterium is a plant pathogen known as Conoplea globosa, which causes a canker disease of oak and several other hardwood tree species.

<i>Armillaria novae-zelandiae</i> Species of fungus

Armillaria novae-zelandiae is a species of mushroom-forming fungus in the family Physalacriaceae. This plant pathogen species is one of three Armillaria species that have been identified in New Zealand.

<span class="mw-page-title-main">Mycoforestry</span>

Mycoforestry is an ecological forest management system implemented to enhance forest ecosystems and plant communities through the introduction of mycorrhizal and saprotrophic fungi. Mycoforestry is considered a type of permaculture and can be implemented as a beneficial component of an agroforestry system. Mycoforestry can enhance the yields of tree crops and produce edible mushrooms, an economically valuable product. By integrating plant-fungal associations into a forestry management system, native forests can be preserved, wood waste can be recycled back into the ecosystem, carbon sequestration can be increased, planted restoration sites are enhanced, and the sustainability of forest ecosystems are improved. Mycoforestry is an alternative to the practice of clearcutting, which removes dead wood from forests, thereby diminishing nutrient availability and reducing soil depth.

<i>Geopora cooperi</i> Species of fungus

Geopora cooperi, commonly known as the pine truffle or the fuzzy truffle, is a species of fungus in the family Pyronemataceae. It has a fuzzy brown outer surface and an inner surface of whitish, convoluted folds of tissue. Widely distributed in the Northern Hemisphere, the species has been recorded from Asia, Europe, and North America.

<i>Suillus pungens</i> Species of fungus in the family Suillaceae found in California

Suillus pungens, commonly known as the pungent slippery jack or the pungent suillus, is a species of fungus in the genus Suillus. The fruit bodies of the fungus have slimy convex caps up to 14 cm (5.5 in) wide. The mushroom is characterized by the very distinct color changes that occur in the cap throughout development. Typically, the young cap is whitish, later becoming grayish-olive to reddish-brown or a mottled combination of these colors. The mushroom has a dotted stem (stipe) up to 7 cm (2.8 in) long, and 2 cm (0.8 in) thick. On the underside on the cap is the spore-bearing tissue consisting of minute vertically arranged tubes that appear as a surface of angular, yellowish pores. The presence of milky droplets on the pore surface of young individuals, especially in humid environments, is a characteristic feature of this species. S. pungens can usually be distinguished from other similar Suillus species by differences in distribution, odor and taste. The mushroom is considered edible, but not highly regarded.

<i>Armillaria ostoyae</i> Species of fungus

Armillaria ostoyae is a species of fungus (mushroom), pathogenic to trees, in the family Physalacriaceae. In the western United States, it is the most common variant of the group of species under the name Armillaria mellea. A. ostoyae is common on both hardwood and conifer wood in forests west of the Cascade Range in Oregon, United States. It has decurrent gills and the stipe has a ring. The mycelium invades the sapwood and is able to disseminate over great distances under the bark or between trees in the form of black rhizomorphs ("shoestrings"). In most areas of North America, Armillaria ostoyae can be separated from other species by its physical features: cream-brown colors, prominent cap scales, and a well-developed stem ring distinguish it from other Armillaria.

<i>Fusarium circinatum</i> Species of fungus

Fusarium circinatum is a fungal plant pathogen that causes the serious disease pitch canker on pine trees and Douglas firs. The most common hosts of the pathogen include slash pine, loblolly pine, Monterey pine, Mexican weeping pine, and Douglas fir. Like other Fusarium species in the phylum Ascomycota, it is the asexual reproductive state of the fungus and has a teleomorph, Gibberella circinata.

<i>Heterobasidion irregulare</i> Species of fungus

Heterobasidion irregulare is a tree root rotting pathogenic fungus that belongs to the genus Heterobasidion, which includes important pathogens of conifers and other woody plants. It has a wide host and geographic range throughout North America and causes considerable economic damage in pine plantations in the United States. This fungus is also a serious worry in eastern Canada. Heterobasidion irregulare has been introduced to Italy (Lazio)(modifica) where it has been responsible for extensive tree mortality of stone pine. Due to the ecology, disease type, host range/preference, interfertility group, and genetic information, H. irregulare was designated a new species and distinguished from Heterobasidion occidentale.

<span class="mw-page-title-main">Ectomycorrhiza</span> Non-penetrative symbiotic association between a fungus and the roots of a vascular plant

An ectomycorrhiza is a form of symbiotic relationship that occurs between a fungal symbiont, or mycobiont, and the roots of various plant species. The mycobiont is often from the phyla Basidiomycota and Ascomycota, and more rarely from the Zygomycota. Ectomycorrhizas form on the roots of around 2% of plant species, usually woody plants, including species from the birch, dipterocarp, myrtle, beech, willow, pine and rose families. Research on ectomycorrhizas is increasingly important in areas such as ecosystem management and restoration, forestry and agriculture.

<span class="mw-page-title-main">Pine-pine gall rust</span> Fungal disease of pine trees

Pine-pine gall rust, also known as western gall rust, is a fungal disease of pine trees. It is caused by Endocronartium harknessii, an autoecious, endocyclic, rust fungus that grows in the vascular cambium of the host. The disease is found on pine trees with two or three needles, such as ponderosa pine, jack pine and scots pine. It is very similar to pine-oak gall rust, but its second host is another Pinus species. The fungal infection results in gall formation on branches or trunks of infected hosts. Gall formation is typically not detrimental to old trees, but has been known to kill younger, less stable saplings. Galls can vary from small growths on branch extremities to grapefruit-sized galls on trunks.

References

  1. Fries EM. (1815). "Observationes mycologicae" (in Latin). 1. Copenhagen: Gerhard Bonnier: 164.{{cite journal}}: Cite journal requires |journal= (help)
  2. 1 2 "GSD Species Synonymy: Rhizina undulata Fr". Species Fungorum. CAB International. Retrieved 2014-01-16.
  3. Schaeffer JC. (1774). Fungorum qui in Bavaria et Palatinatu circa Ratisbonam nascuntur Icones (in Latin). Vol. 4. Regensburg. p. 102.
  4. Roody WC. (2003). Mushrooms of West Virginia and the Central Appalachians. Lexington, Kentucky: University Press of Kentucky. p. 468. ISBN   978-0-8131-9039-6.
  5. McKnight VB, McKnight KH (1987). A Field Guide to Mushrooms: North America . Peterson Field Guides. Boston, Massachusetts: Houghton Mifflin. p.  54. ISBN   978-0-395-91090-0.
  6. Phillips R. "Rhizina undulata". Rogers Plants. Archived from the original on 2010-12-31. Retrieved 2009-02-12.
  7. 1 2 3 Tylutki EE. (1979). Mushrooms of Idaho and the Pacific Northwest. Moscow, Idaho: University Press of Idaho. p. 96. ISBN   0-89301-062-6.
  8. 1 2 Fitzpatrick HM. (1917). "The development of the ascocarp of Rhizina undulata Fr". Botanical Gazette. 63 (4): 282–296. doi: 10.1086/332025 . JSTOR   2468962. S2CID   84825906.
  9. Courtecuisse R. (1999). Mushrooms of Britain and Europe. Collins Wildlife Trust Guides. London, UK: Harpercollins. p. 292. ISBN   978-0-00-220012-7.
  10. 1 2 3 Compendium of Conifer Diseases. APS Press. 1997. ISBN   0-89054-183-3.
  11. Samuelson DA. (1978). "Asci of the Pezizales. 6. Apical apparatus of Morchella esculenta, Helvella crispa, and Rhizina undulata". Canadian Journal of Botany. 56 (24): 3069–82. doi:10.1139/b78-370.
  12. 1 2 Roberts P, Evans S (2011). The Book of Fungi. Chicago, Illinois: University of Chicago Press. p. 585. ISBN   978-0-22-672117-0.
  13. Jallaludin M. (1967). "Studies of Rhizina undulata. I. Mycelial growth and ascopspore germination". Transactions of the British Mycological Society. 50 (3): 449–459. doi:10.1016/s0007-1536(67)80014-7.
  14. Jallaludin M. (1967). "Studies of Rhizina undulata. II. Observations and experiments in East Anglian plantations". Transactions of the British Mycological Society. 50 (3): 461–472. doi:10.1016/s0007-1536(67)80015-9.
  15. Ginns JH. (1968). "Rhizina undulata pathogenic on Douglas fir seedlings in western North America". Plant Disease Reporter. 52 (7): 579–80.
  16. Brooks FT. (1910). "Rhizina undulata". Quarterly Journal of Forestry. 4: 308–309.
  17. 1 2 Weir JR. (1915). "Observations on Rhizina inflata". Journal of Agricultural Research. 4: 93–97.
  18. Hartig R. "Untersuchungen über Rhizina undulala". Botanisches Centralblatt (in German). 45: 237–238.
  19. Hartig R. (1892). "Rhizina undulala Fr. Der Wurzelschwamm". Forstarchiv Forstlich-naturwissenschaftliche Zeitschrift (in German). 1: 291–297.
  20. 1 2 Hartig R. (1894). Text-book of the Diseases of Trees. London, UK: Macmillan. pp. 123–129.
  21. Hartig R. (1900). Lehrbuch der Pflanzenkrankheiten (in German). Berlin: Verlag von Julius Springer.
  22. 1 2 Gremmen J. (1961). "Afsterving van naaldhout door Rhizina undulata, in het bijzonder na takken – branden op kaalslagen" [A die-back of conifers caused by Rhizina undulata, particularly after slash burning]. Nederlands Bosbouw Tijdschrift (in Dutch). 33 (1): 5–10.
  23. 1 2 Murray JS, Young CW (1961). Group Dying of Conifers (Report). London, UK: Forestry Commission Forest Record.
  24. Hardison JR. (1976). "Fire and flame for plant disease control". Annual Review of Phytopathology. 14 (1): 355–79. doi:10.1146/annurev.py.14.090176.002035.
  25. Gremmen J. (1971). "Rhizina undulata: A review of research in the Netherlands". European Journal of Forest Pathology. 1 (1): 1–6. doi:10.1111/j.1439-0329.1971.tb00283.x.
  26. Vasiliauskas R, Stenlid J (2001). "Homothallism in the postfire ascomycete Rhizina undulata". Mycologia. 93 (3): 447–452. doi:10.2307/3761730. JSTOR   3761730.
  27. Hagner M. (1962). "Några faktorer av betydelse för rotmurklans skadegörelse" [Some factors affecting damage by Rhizina undulata]. Norrlands Skogsvårdsförbunds Tidskrift (in Swedish). 2: 245–270.
  28. Sato K, Yokozawa Y, Shoji T (1974). "Studies on Rhizina root rot causing group dying of pine trees". Bulletin of the Government Forest Experimental Station (in Japanese). 268: 13–48.
  29. Lee SY, Kim WK (1990). "Studies on Rhizina root rot disease of Pinus densiflora: physiological characteristics and pathogenicity of Rhizina undulata". Journal of the Korean Forestry Society. 79: 322–329.
  30. Vasiliauskas AP. (1999). "Distribution of Heterobasidion annosum and Rhizina undulata in mountain pine (Pinus mugo) plantations on Kuronian spit". Mikologiya i Fitopatologiya. 33 (3): 276–279.