Pachnocybe

Pachnocybe
Scientific classification
Kingdom:	Fungi
Division:	Basidiomycota
Class:	Pucciniomycetes
Order:	Pachnocybales
Family:	Pachnocybaceae Oberw. & R.Bauer
Genus:	Pachnocybe Berk.[1]

The Pachnocybe are a genus of fungi, within the monotypic family of Pachnocybaceae Oberw. & R.Bauer, 1989,^[2] and within the monotypic order of Pachnocybales, within the class Pucciniomycetes.^[3] They are parasitic on plants or saprobic on rotten wood.

History

The genus of Pachnocybe was created in 1836, when English cryptogamist Miles Joseph Berkeley moved several species from other genera into his new genus.^[1] Such as Sporocybe albida became Pachnocybe albida.^[4][5]

The genus name of Pachnocybe was derived from Greek word Pachne meaning hoar-frost and also cybe meaning head.^[5]

Hughes in 1958 in his review of classical hyphomycete genera selected Pachnocybe ferruginea as type species of the genus. He also excluded Pachnocybe grisea as a synonym of Cephalotrichum purpureofuscum (in the family Microascaceae).^[6]

The genus Pachnocybe was then assigned as fungi imperfecti by Ellis in 1971,^[7] then in 1980 Carmichael et al. suggested it had an ascomycetous relationship.^[8] Then Oberwinkler and Bandoni in 1982, after studying the morphology of species Pachnocybe ferruginea found strong basidiomycetous relationships.^[9] In 1986, Kropp and Corden proposed it should be placed in the Chionosphaeraceae family.^[10]

The genus was later placed in order Atractiellales,^[11] due to species in the group having gastroid basidia and simple septal pores.^[10]

The genus Pachnocybe was placed in family Septobasidiaceae (Septobasidiales order), even though many Septobasidiaceae species were mostly parasitic on scale insects.^[12] The family placement was based on weakly supported phylogenetic inference,^[13] and the reported presence of 'microscala', (which are membrane complexes, consisting of layers of membranes of endoplasmic reticulum, interconnected by a regular array of rodlets which may also connect to the mitochondria^[14]) (Kleven and McLaughlin, 1989;^[15] Bauer and Oberwinkler, 1990).^[16]

Description

They were originally described in 1836 and 1863 as having "a solid stem, filiform below, clavate above, dusted with minute spores".^[17]

Species in the Pachnocybaceae family have a basidiomata (spore stem) that stilboid (pin-shaped), stipitate (possessing a stipe, stem) and capitate (resembles the head of a pin), smooth, not viscid or gelatinous in form. The fertile head is globose (rounded), hyaline (glass-like) or pale yellowish, with the entire surface composed of packed basidia (spore-producing structures). The dark reddish brown stipe is composed of closely adherent thick walled hyphae (long, branching, filamentous structure). The hyphae have simple septal spores, with no clamp connections and fertile hyphae are frequently branched. The basidia is clavate to cylindrical (in form), aseptate (undivided), with basal clamp connections and an apical cluster of 4-6 minute sterigmata (small supporting structures). The basidiospores are ellipsoidal (in form), hyaline or yellowish with smooth and thick walls.^[18]

Pachnocybe ferruginea was thought to be a dikaryotic mycelium that formed brown capitate basidiocarps. However, one form had associated blastic-sympodial conidia, larger basidiocarps, chlamydospores, and had a slower growth rate. Single uninucleate basidiospores of both forms produced dikaryotic mycelium with simple septal pores and holobasidia in which karogamy and meiosis occurred. Thus, P. ferruginea has a primary homothallic life cycle. Spores from conidial isolates gave rise to both basidiocarps and the conidial form demonstrating that the conidial form is the anamorph of P. ferruginea.^[10]

They have a primary homothallic life cycle.^[10]

List of species

The genus Pachnocybe contain 4 known species;^[19]

• Pachnocybe acicula Berk. (1836)
• Pachnocybe albida (Fr.) Berk. (1836)
• Pachnocybe ferruginea Berk. (1836)^[10]
• Pachnocybe incerta (P. Karst.) S. Hughes (1958)

Former species;^[19]

• Pachnocybe clavulata Grove (1885) = Phaeoisaria clavulata Diatrypaceae
• Pachnocybe grisea Berk. (1836) = Cephalotrichum purpureofuscum Microascaceae

2 other species are noted elsewhere but not listed in Species Fungorum.

• Pachnocybe rosea Berk. & M.A. Curtis (found on the wood of Acacia julibrissin in America) ^[20][21]
• Pachnocybe subulata (Nees & T. Nees) Berk. (found on the bark of Robinia pseudoacacia species, ^[22] and in Scotland, on decaying plants and fir cones,^[23])

Hosts

Pachnocybe ferruginea has been found on domestic wood, such as pine floorboards in a house,^[24] on a wine cask and also on timbers inside a mine (Levy and Lloyd, 1960,^[25]) within the UK.^[26] It was also found in Douglas fir (Pseudotsuga menziesii) made utility poles in western Oregon, USA.^[10][27]

Distribution

The order has a scattered distribution, they are recorded mostly in Europe, North America (including Canada,^[18]), some in Africa and rarely in India and the Pacific Ocean.^[28] They can be found in terrestrial and aquatic environments.^[29]

Species Pachnocybe albida has been found on rotten logs of Buxus, Fraxinus and Quercus.^[30]

References

1. Smith, James Edward (1836). Hooker, William Jackson; Berkeley, Miles Joseph (eds.). The English Flora of Sir James Edward Smith. Vol. 5, part II: "Class XXIV. Cryptogamia". London, England: Longman, Rees, Orme, Brown, Green & Longman. p. 2.
2. Oberwinkler, F.; Bauer, R. (1989). "The systematics of gasteroid, auricularioid Heterobasidiomycetes". Sydowia. 41: 224–256.
3. Wijayawardene, Nalin; Hyde, Kevin; Al-Ani, Laith Khalil Tawfeeq; Somayeh, Dolatabadi; Stadler, Marc; Haelewaters, Danny; et al. (2020). "Outline of Fungi and fungus-like taxa". Mycosphere. 11: 1060–1456. doi:10.5943/mycosphere/11/1/8. hdl:10481/61998.
4. James Edward Smith and Miles Joseph Berkeley English Flora: Class 24, Cryptogamia, Pt. 2, comprising ..., Volume 5, Issue 2 (1836), p. 33, at Google Books
5. Henrici, Alick (January 2020). "Pachnocybe' albida - unfairly neglected". Field Mycology. 21 (1): 15–17. doi:10.1016/j.fldmyc.2020.01.006. S2CID 214494102.
6. Hughes, S.J. (1958). "Revisiones hyphomycetum aliquot cum appendice de nominis rejiciendis". Can. J. Bot. 36 (6): 727–836. doi:10.1139/b58-067.
7. Ellis, M.B. (1971). Dematiaceous Hyphomycetes. Kew, Surrey, England: Commonwealth Mycological Institute. p. 608.
8. Carmichael, J.W.; Kendrick, W.B.; Conners, I.L.; Sigler, L. (1980). Genera of Hyphomycetes. Alberta, Canada: University of Alberta Press.
9. Oberwinkler, F.; Bandoni, R.J. (1982). "A taxonomic survey of the gastroid, auricularioid Heterobasidiomycetes". Can. J. Bot. 60 (9): 1726–1750. doi:10.1139/b82-221.
10. Kropp, Bradley R.; Corden, Malcolm E. (May–June 1986). "Morphology and Taxonomy of Pachnocybe ferruginea". Mycologia. 78 (3): 334–342. doi:10.1080/00275514.1986.12025255.
11. Walker, William F. (October 1984). "5S rRNA sequences from Atractiellales, and Basidiomycetous yeasts and fungi imperfecti". Systematic and Applied Microbiology. 5 (3): 352–359. doi:10.1016/S0723-2020(84)80037-5.
12. Henk, Daniel A.; Vilgalys, Rytas (September 2007). "Molecular phylogeny suggests a single origin of insect symbiosis in the Pucciniomycetes with support for some relationships within the genus Septobasidium". American Journal of Botany. 94 (9): 1515–1526. doi:10.3732/ajb.94.9.1515. PMID 21636518.
13. Frieders, E. M. 1997. An integrated approach to understanding the moss parasites and their role in basidiomycete evolution. Ph.D. dissertation, University of Minnesota, St. Paul, Minnesota, USA.
14. David J. McLaughlin and Joseph W. Spatafora (Editors) Systematics and Evolution (2013), p. 46, at Google Books
15. Kleven, N.J.; McLaughlin, D.J. (1989). "A light and electron microscopic study of the developmental cycle in the basidiomycete Pachnocybe ferruginea". Canadian Journal of Botany. 67 (5): 1336–1348. doi:10.1139/b89-178.
16. Bauer, R.; Oberwinkler, F. (1990). "Meiosis, spindle pole body cycle, and taxonomy of the heterobasidiomycete Pachnocybe ferruginea". Plant Systematics and Evolution. 172 (1–4): 241–261. doi:10.1007/BF00937810. S2CID 20001667.
17. Mordecai Cubitt Cooke Handbook of British Fungi, with full descriptions of all the species and illustrations of the genera, Volume 2 (1863), p. 550, at Google Books
18. P. F. Cannon and P. M. Kirk (Editors) Fungal Families of the World (2006), p. 253, at Google Books
19. "Pachnocybe - Search Page". www.speciesfungorum.org. Species Fungorum. Retrieved 4 October 2022.
20. M.C. Cooke (Editor) Grevillea: a monthly record of cryptogamic botany and its literature, Volume 3 (1874), p. 62, at Google Books
21. Buffalo Society of Natural Sciences Bulletin of the Buffalo Society of Natural Sciences, Volume 3, Issues 4-5 (1877), p. 195, at Google Books
22. William Gilson Farlow, Arthur Bliss Seymour and A. B. Seymour A Provisional Host-index of the Fungi of the United States, Part 1 (1888), p. 28, at Google Books
23. George Dickie The Botanist's Guide to the Counties of Aberdeen, Banff, and Kincardine (1860), p. 334, at Google Books
24. Mason, E.W.; Ellis, M.B. (1953). "British species of Periconia". Mycological Papers. 56: 1–127.
25. Levy, J.F.; Lloyd, F.J. (1960). "A study of the fungi present in timbers in Tywarnhale Mine (Cornwall)". Journal of the Institute of Wood Science.
26. Legon, N.W.; Henrici, A.; Roberts, P.J.; Spooner, B.M.; Watling, R. (2005). Checklist of the British and Irish Basidiomycota. London, U.K.: Royal Botanic Gardens, Kew. ISBN 1-84246-121-4.
27. Chun-Juan Wang and Robert A. Zabel Identification Manual for Fungi from Utility Poles in the Eastern United States (1990), p. 161, at Google Books
28. "Pachnocybales". www.gbif.org. Retrieved 28 August 2023.
29. Kleven, N.L.; McLaughlin, D.J. (1988). "Sporulation of the Basidiomycete Pachnocybe ferruginea in Terrestrial and Aquatic Environments". Mycologia. 80 (6): 804–810. doi:10.1080/00275514.1988.12025727.
30. Ellis, M.B.; Ellis, J.P. (1985). Microfungi on Land Plants (2nd Edn. (1997) ed.). London: Croom Helm.

Other sources

• C.J. Alexopolous, Charles W. Mims, M. Blackwell et al., Introductory Mycology, 4th ed. (John Wiley and Sons, Hoboken NJ, 2004) ISBN 0-471-52229-5