Problems and prospects in the systematics of the Ascomycotina

  • D L Hawksworth


The classification of the Ascomycotina remains one of the major problems in systematic mycology. A survey of the various systems proposed over the last five decades is presented identifying their key aspects. A table including outlines of 20 systems is provided. Constraints to developing a generally acceptable system are identified as arising from the size of the group, its geological age, assumption of phylogenetic concepts, data availability, convergence, delimitation of genera, and taxa remaining to be discovered. Progress towards an acceptable system must pay due regard to the users of taxonomy and have strong elements of stability. Data collection could be approached by concerted efforts of groups of specialists tackling particular orders in turn. It seems most appropriate to progress by building up the hierarchy from maximum information content groups, concentrating on delimiting monophyletic units in the ranks of order and family, and restricting hypothetical overall systems to specialist debate rather than recommending them for general use.


Fungi Ascomycotina lichens systematics classification 


  1. Ainsworth G C, James P W and Hawksworth D L 1971Ainsworth and Bisby’s dictionary of the fungi, 6th edn (Kew: Commonwealth Mycological Institute)Google Scholar
  2. Ainsworth G C, Sparrow F K and Sussman A S (eds) 1973The fungi: an advanced treatise, (New York, London: Academic Press) vol. 4AGoogle Scholar
  3. Allkin R and Bisby F A (eds) 1984Databases in systematics (London: Academic Press)Google Scholar
  4. von Arx J A 1973 Ostiolate and non-ostiolate Pyrenomycetes;Proc. K. Ned. Akad. Wet. C 76 289–296Google Scholar
  5. von Arx J A 1979 Ascomycetes as fungi imperfecti; inThe whole fungus (ed.) B Kendrick (Ottawa: National Museum of Canada) 201–213Google Scholar
  6. von Arx J A 1981The genera of fungi sporulating in pure culture, 3rd edn (Vaduz: Cramer)Google Scholar
  7. von Arx J A, Walt J P van der and Liebenberg N V D M 1982 The classification ofTaphrina and other fungi with yeast-like cultural states;Mycologia 74 284–296Google Scholar
  8. von Arx J A, Müller E 1954 Die Gattungen der amerosporen Pyrenomyceten;Beitr. Kryptogamenflora Schweiz 1 1–434Google Scholar
  9. von Arx J A and Müller E 1975 A re-evaluation of the bitunicate ascomycetes with keys to families and genera;Stud. Mycol. 9 1–159Google Scholar
  10. Barr M E 1976 Perspectives in the Ascomycotina;Mem. N.Y. Bot. Gdn 28 1–8Google Scholar
  11. Barr M E 1979 A classification of Loculoascomycetes;Mycologia 71 935–957CrossRefGoogle Scholar
  12. Barr M E 1983 The ascomycete connection;Mycologia 75 1–13CrossRefGoogle Scholar
  13. Bellemère A 1968 “1967” Contribution a l’étude de développement de l’apothécie chez les discomycètes inoperculés;Bull. Soc. Mycol. Fr. 83 395–931Google Scholar
  14. Bellemère A 1971 Les asques et des apothécies des discomycètes bituniqués;Ann. Sci. Nat., Bot. Biol. Vég. 12 429–464Google Scholar
  15. Benny G L and Kimbrough J W 1980 A synopsis of the orders and families of Plectomycetes with keys to genera;Mycotaxon 12 1–91Google Scholar
  16. Bessey E A 1935A text-book of mycology (Philadelphia: Blakiston’s)Google Scholar
  17. Booth C 1966 Fruit bodies in ascomycetes; inThe fungi: an advanced treatise (eds) G C Ainsworth and A S Sussman (New York etc: Academic Press)2 133–150Google Scholar
  18. Cain R F 1972 Evolution of the fungi;Mycologia 60 1–14CrossRefGoogle Scholar
  19. Cannon P F, Hawksworth D L and Sherwood-Pike M A 1985The British Ascomycotina. An annotated checklist (Kew: Commonwealth Mycological Institute)Google Scholar
  20. Chadefaud M 1960 Les vegetaux non vasculaires (Cryptogamie);Traité de botanique systématique (eds) M Chadefaud and L Emberger (Paris: Masson) vol. I.Google Scholar
  21. Chadefaud M 1973 Les asques et la systématique des Ascomycètes;Bull. Soc. Mycol. Fr. 89 127–170Google Scholar
  22. Chadefaud M 1982a Les principaux types d’ascocarpes: leur organisation et leur evolution;Cryptog., Mycol. 3 1–9Google Scholar
  23. Chadefaud M 1982b Les principaux types d’ascocarpes: leur organisation et leur evolution; Deuxième partie: Les discocarpes;Cryptog., Mycol. 3 103–144Google Scholar
  24. Chadefaud M, Letrouit-Galinou M-A and Janex-Favre M-C 1970 “1969” Sur l’origine phylogénétique et l’evolution des Ascomycètes des lichens;Mém. Soc. bot. Fr. 1968 79–111Google Scholar
  25. Chesters C G C 1938 Studies on British pyrenomycetes II. A comparative study ofMelanomma pulvis-pyrius (Pers.) Fuckel,Melanomma fuscidulum Sacc. andThyridaria rubro-notata (B. & Br.) Sacc.;Trans. Br. Mycol. Soc. 22 116–150Google Scholar
  26. Clements F E 1909The genera of fungi (Minneapolis: Wilson)Google Scholar
  27. Clements F E and Shear C L 1931The genera of fungi (New York: Wilson)Google Scholar
  28. Cooke W B and Hawksworth D L 1970 A preliminary list of the families proposed for fungi (including the lichens);Mycol. Pap. 121 1–86Google Scholar
  29. Culberson C F 1969Chemical and botanical guide to lichen products (Chapel Hill: University of North Carolina Press)Google Scholar
  30. Culberson C F 1970 Supplement to “Chemical and botanical guide to lichen products”;Bryologist 73 177–377CrossRefGoogle Scholar
  31. Culberson C F, Culberson W L and Johnson A 1977Second supplement to “Chemical and Botanical guide to lichen products” (St. Louis: American Bryological and Lichenological Society)Google Scholar
  32. Curry K J and Kimbrough J W 1983 Septal structures in apothecial tissues of the Pezizaceae (Pezizales, Ascomycetes);Mycologia 75 781–794CrossRefGoogle Scholar
  33. Demoulin V 1975 The origin of Ascomycetes and Basidiomycetes. The case for a red algal ancestry;Bot. Rev. 40 315–345CrossRefGoogle Scholar
  34. Döbbeler P 1978 Moosbewohnende Ascomyceten I. Die Pyrenocarpen, den Gametophyten besiedelnden Arten;Mitt. Bot. Staatssamml. Muencho 14 1–360Google Scholar
  35. Eriksson O 1981 The families of bitunicate ascomycetes;Opera Bot. 60 1–220.Google Scholar
  36. Eriksson O 1982 Outline of the ascomycetes — 1982;Mycotaxon 15 203–248Google Scholar
  37. Eriksson O 1983 Outline of the ascomycetes — 1983;Systema Ascom 2 1–37Google Scholar
  38. Gäumann E 1964Die Pilze. Grundzüge ihrer Entwichlungsgeschichte und Morphologie, 2nd edn (Basel and Stuttgart: Birkäuser)Google Scholar
  39. Hafellner J 1979Karschia. Revision einer Sammelgattung an der Grenze von lichenisierten und nichtlichenisierten Ascomyceten;Beih. Nova Hedwigia 62 1–248Google Scholar
  40. Hale M E 1967The biology of lichens (London: Arnold)Google Scholar
  41. Hansford C G 1946 The foliicolous Ascomycetes their parasites and associated fungi;Mycol. Pap. 15 1–240Google Scholar
  42. Hawksworth D L 1978 The taxonomy of lichen-forming fungi: reflections on some fundamental problems; inEssays in plant taxonomy (ed.) H E Street (London etc: Academic Press) 212–243Google Scholar
  43. Hawksworth D L 1981 A survey of the fungicolous conidial fungi; inThe biology of conidial fungi (eds) G T Cole and B Kendrick (New York etc: Academic Press)1 171–244Google Scholar
  44. Hawksworth D L 1982 Co-evolution and the detection of ancestry in lichens;J. Hattori Bot. Lab. 52 323–329Google Scholar
  45. Hawksworth D L 1984 Recent changes in the international rules affecting the nomenclature of fungi;Microbiol. Sci. 1 18–21PubMedGoogle Scholar
  46. Hawksworth D L, Sutton B C and Ainsworth G C 1983Ainsworth and Bisby’s dictionary of the fungi, 7th edn (Kew: Commonwealth Mycological Institute)Google Scholar
  47. Hawksworth D L and Whalley A J S 1985 A new species ofRhopalostroma with aNodulisporium anamorph from Thailand;Trans. Br. Mycol. Soc. 84 (in press)Google Scholar
  48. Henssen A 1963 Eine Revision der Flectenfamilien Lichinaceae und Ephebaceae;Symb. Bot. Upsal. 18(1) 1–123.Google Scholar
  49. Henssen A and Jahns H M 1973 “1974”Lichenes. Eine Einführung in die Flechtenkunde (Stuttgart: Thieme)Google Scholar
  50. Heywood V H (ed.) 1971The biology and chemistry of the Umbelliferae (London and New York: Academic Press)Google Scholar
  51. Heywood V H 1983 The mythology of taxonomy;Trans. Bot. Soc. Edinburgh 44 79–94Google Scholar
  52. Heywood V H, Harborne J B and Turner B L (eds) 1977The biology and chemistry of the Compositae; (London: Academic Press) 2 volsGoogle Scholar
  53. Holm L and Holm K 1977 A study of the Leptopeltidaceae;Bot. Not. 130 215–229Google Scholar
  54. Honegger R 1978aLicht-und elektronenoptische Untersuchungen an Flechten-Asci von Lecanora-typ (Basel: Universitat)Google Scholar
  55. Honegger R 1978b The ascus apex in lichenized fungi I. TheLecanora, Peltigera- andTeloschistes-types;Lichenologist 10 47–67CrossRefGoogle Scholar
  56. Honegger R 1978c Ascocarpontogenie, Ascusstruktur und-funktion bei Vertretern der GattungRhizocarpon;Ber. Dtsch. Bot. Ges. 91 579–594Google Scholar
  57. Honegger R 1980 The ascus apex in lichenized fungi II. TheRhizocarpon-type;Lichenologist 12 157–171CrossRefGoogle Scholar
  58. Honegger R 1982a Ascus structure and function, ascospore delimitation, and phycobiont cell wall types associated with the Lecanorales (lichenized ascomycetes);J. Hattori Bot. Lab. 52 417–429Google Scholar
  59. Honegger R 1982b The ascus apex in lichenized-fungi III. ThePertusaria-type;Lichenologist 14 205–217CrossRefGoogle Scholar
  60. Honegger R 1983 The ascus apex in lichenized fungi IV.Baeomyces andIcmadophila in comparison withCladonia (Lecanorales) and the non-lichenizedLeotia (Helotiales);Lichenologist 15 57–71CrossRefGoogle Scholar
  61. Janex M-C 1971 Recherches sur l’ontogénie, l’organisation et les asques de quelques pyrènolichens;Rev. Bryol. Lichénol. 37 421–650Google Scholar
  62. Kendrick W B (ed) 1971Taxonomy of fungi imperfecti (Toronto: University Press)Google Scholar
  63. Kendrick W B (ed.) 1979The whole fungus, (Ottawa: National Museums of Canada) 2 volsGoogle Scholar
  64. Kohlmeyer J and Kohlmeyer E 1979Marine mycology. The higher fungi (New York: Academic Press)Google Scholar
  65. Korf R P 1983Cyttaria (Cyttariales): coevolution withNothofagus, and evolutionary relationship to the Boedijnopezizeae (Pezizales, Sarcoscyphaceae);Aust. J. Bot., Suppl. 10 77–87Google Scholar
  66. Kreisel H 1969Grundzüge eines natürlichen Systems der Pilze (Jena: Gustav Fischer)Google Scholar
  67. Letrouit-Galinou M-A 1967 “1966” Recherches sur l’ontogénie et l’anatomie comparative des apothécies de quelques Discolichens;Rev. Bryol. Lichénol. 34 413–588Google Scholar
  68. Letrouit-Galinou M-A 1969 “1968” The apothecia of the discolichens;Bryologist 71 297–327Google Scholar
  69. Letrouit-Galinou M-A 1973 Les asques des lichens et le type archaeascé;Bryologist 76 30–47CrossRefGoogle Scholar
  70. Lindsay W L 1869 Observations on new lichenicolous micro-fungi;Trans. R. Soc. Edinburgh 25 513–555Google Scholar
  71. Locquin M V 1984Mycologie générale et structurale (Paris, etc.: Masson)Google Scholar
  72. Luttrell E S 1951 Taxonomy of the pyrenomycetes;Univ. Mo. Stud. 24 1–120 [reprinted asBibl. Mycol. 6 1967]Google Scholar
  73. Luttrell E S 1955 The ascostromatic Ascomycetes;Mycologia 47 511–531CrossRefGoogle Scholar
  74. Machol R E 1984 Leave the Code alone;Taxon 33 532–533CrossRefGoogle Scholar
  75. Malloch D W 1981 The plectomycete centrum; inAscomycete systematics: The Luttrellian concept (ed.) D R Reynolds 73–91 (New York: Springer Verlag)Google Scholar
  76. Miller J H 1949 A revision of the classification of the Ascomycetes with special emphasis on the Pyrenomycetes;Mycologia 41 99–127CrossRefGoogle Scholar
  77. Minter D W and Cannon P F 1984 Ascospore discharge in some members of the Rhytismataceae;Trans. Br. Mycol. Soc. 83 65–92Google Scholar
  78. Müller E and von Arx J A 1950 Einige Aspekte zur Systematik pseudospharialer Ascomyceten;Ber. Schweiz. Bot. Ges. 60 329–397Google Scholar
  79. Müller E and von Arx J A 1962 Die Gattungen der didymosporen Pyrenomyceten;Beitr. Kryptogamenflora Schweiz 11 1–922Google Scholar
  80. Nannfeldt J A 1932 Studien über die Morphologie und systematik der nich-lichenisierten inoperculaten Discomyceten;Nova Acta R. Soc. Scient. Upsal. IV8 1–368Google Scholar
  81. Nannfeldt J A 1976 Iodine reactions in ascus plugs and their taxonomic significance;Trans. Br. Mycol. Soc. 67 283–287Google Scholar
  82. Parguey-Leduc A 1966 Recherches sur l’ontogenie et l’anatomie comparée des ascocarpes des pyrenomycetes ascoloculaires;Ann. Sci. Nat., Bot. XII7 505–590Google Scholar
  83. Petersen R M 1974 Proposals for treatment of fungus family names with vernacular terminations;Taxon 23 654–658CrossRefGoogle Scholar
  84. Pirozynski K A and Weresub L K 1979 A biogeographic view of the history of ascomycetes and the development of their pleomorphism; inThe whole fungus (ed.) B Kendrick (Ottawa: National Museums of Canada)1 93–123Google Scholar
  85. Poelt J 1974 “1973” Classification; inThe lichens (eds) V Ahmadjian and M E Hale (New York and London: Academic Press) 599–632Google Scholar
  86. Polhill R M and Raven P H 1981Advances in legume systematics (Kew: Royal Botanic Gardens) 2 volsGoogle Scholar
  87. Prance G T 1984 Completing the inventory; inCurrent concepts in plant taxonomy (eds) V H Heywood and D M Moore (London: Academic Press) 365–396Google Scholar
  88. Punithalingam E 1983 The nuclei ofMacrophomina phaseolina (Tassi) Goid.;Nova Hedwigia 38 339–367Google Scholar
  89. Reynolds D R (ed.) 1981Ascomycete systematics. The Luttrellian concept (New York: Springer Verlag)Google Scholar
  90. Richardson D H S 1970 Ascus and ascocarp structure in lichens;Lichenologist 4 350–361CrossRefGoogle Scholar
  91. Samuels G J and Müller E 1980 Life-history studies of Brazilian ascomycetes 8;Sydowia 33 274–281Google Scholar
  92. Santesson R 1949Dolichocarpus andXanthopeltis, two new lichen genera from Chile;Sven. Bot. Tidskr. 43 547–567Google Scholar
  93. Santesson R 1952 Foliicolous lichens I. A revision of the taxonomy of the obligately foliicolous lichenized fungi;Symb. Bot. Upsal. 12(1) 1–590Google Scholar
  94. Santesson R 1953 The new systematics of lichenized fungi; inProc. Seventh Int. Bot. Cong., Stockholm 1950 (eds) H Osvald and E Åberg (Stockholm: Almqvist and Wiksell) 809–810Google Scholar
  95. Santesson R 1967 On taxonomical and biological relations between lichens and non-lichenized fungi;Bot. Not. 120 497–498Google Scholar
  96. Sharma A K and Koul A K 1984 Chromosomal variability inPhyllactina (Erysiphaceae);Trans. Br. Mycol. Soc. 82 355–359Google Scholar
  97. Sheard J W 1977 Palaeogeography, chemistry and taxonomy of the lichenized ascomycetesDimeleana andThamnolia;Bryologist 80 100–118CrossRefGoogle Scholar
  98. Sherwood M A 1981 Convergent evolution in discomycetes from bark and wood;Bot. J. Linn. Soc. 82 15–34CrossRefGoogle Scholar
  99. Sherwood-Pike M A 1985Pelicothallus Dilcher, an overlooked fossil lichen;Lichenologist 17 114–115CrossRefGoogle Scholar
  100. Sherwood M A and Hawksworth D L 1982 Two new families in the Ascomycotina;Mycotaxon 16 262–264Google Scholar
  101. Sipman H 1983 A monograph of the lichen family Megalosporaceae;Bibltheca lich., Vaduz 18 1–241Google Scholar
  102. Sivanesan A 1984The bitunicate ascomycetes and their anamorphs (Vaduz: Cramer)Google Scholar
  103. Solbrig O T and Golley F B 1983 A decade of the tropics;Int. Biol. Spec. Issue 2 1–15Google Scholar
  104. Subramanian C V 1982 Tropical mycology: future needs and development;Cur. Sci. 51 321–325Google Scholar
  105. Tehler 1983 The generaDirina andRoccellina (Roccellaceae);Opera Bot. 70 1–86Google Scholar
  106. Turner W B 1971Fungal metabolites (London and New York: Academic Press)Google Scholar
  107. Turner W B and Aldridge D C 1983Fungal metabolites II (London: Academic Press)Google Scholar
  108. Valadon L R G 1976 Carotenoids as additional taxonomic characters in fungi: a review;Trans. Br. Mycol. Soc. 67 1–15CrossRefGoogle Scholar
  109. Vězda A 1968 Taxonomische Revision der GattungThelopsis Nyl. (lichenisierte Fungi);Folia Geobot. Phytotax. Praha 4 363–406Google Scholar
  110. Watson W 1929 The classification of lichens;New Phytol. 28 1–36, 85–116CrossRefGoogle Scholar
  111. Wehmeyer L E 1975 The pyrenomycetous fungi;Mycol. Mem. 6 1–250Google Scholar
  112. Weijman A C M and de Hoog G S 1975 On the subdivision ofCeratocystis;Antonie van Leeuwenhoek 41 353–360PubMedCrossRefGoogle Scholar
  113. Weresub L K 1979 Mycological nomenclature: reflections on its future in the light of its past;Sydowia Beih. 8 416–431Google Scholar
  114. Zahlbruckner A 1926 Lichens (Flechten). B. Spezieller Teil;Nat. Pflanzenfam. 8 61–270Google Scholar

Copyright information

© Indian Academy of Sciences 1985

Authors and Affiliations

  • D L Hawksworth
    • 1
  1. 1.Commonwealth Mycological InstituteFerry LaneKewUK

Personalised recommendations