Forma specialis

LifeDomainKingdomPhylumClassOrderFamilyGenusSpecies
The hierarchy of biological classification's eight major taxonomic ranks. Intermediate minor rankings are not shown.

Forma specialis (plural: formae speciales), abbreviated f. sp. (plural ff. spp.) without italics, is an informal taxonomic grouping allowed by the International Code of Nomenclature for algae, fungi, and plants,[1] that is applied to a parasite (most frequently a fungus) which is adapted to a specific host. This classification may be applied by authors who do not feel that a subspecies or variety name is appropriate, and it is therefore not necessary to specify morphological differences that distinguish this form. The literal meaning of the term is 'special form', but this grouping does not correspond to the more formal botanical use of the taxonomic rank of forma or form.

An example is Puccinia graminis f. sp. avenae, which affects oats.[citation needed]

An alternative term in contexts not related to biological nomenclature is physiological race (sometimes also given as biological race, and in that context treated as synonymous with biological form),[2][3] except in that the name of a race is added after the binomial scientific name (and may be arbitrary, e.g. an alphanumeric code, usually with the word "race"), e.g. "Podosphaera xanthii race S".[4] A forma specialis is used as part of the infraspecific scientific name (and follows Latin-based scientific naming conventions), inserted after the interpolation "f. sp.", as in the "Puccinia graminis f. sp. avenae" example.

  1. ^ McNeill, J.; Barrie, F.R.; Buck, W.R.; Demoulin, V.; Greuter, W.; Hawksworth, D.L.; Herendeen, P.S.; Knapp, S.; Marhold, K.; Prado, J.; Prud'homme Van Reine, W.F.; Smith, G.F.; Wiersema, J.H.; Turland, N.J. (2012). International Code of Nomenclature for algae, fungi, and plants (Melbourne Code) adopted by the Eighteenth International Botanical Congress Melbourne, Australia, July 2011. Vol. Regnum Vegetabile 154. A.R.G. Gantner Verlag KG. ISBN 978-3-87429-425-6. Chapter I. Article 4.4. Note 4.
  2. ^ Walker, Peter M. B., ed. (2004) [1999]. "Biological form". Chambers Dictionary of Science and Technology. Edinburgh / New Delhi: Chambers Harrap / Allied Chambers. Previously: The Wordsworth Dictionary of Science and Technology. W. R. Chambers / Cambridge U. Pr. 1998.
  3. ^ Walker, Peter M. B., ed. (2004) [1999]. "Biological race". Chambers Dictionary of Science and Technology. Edinburgh / New Delhi: Chambers Harrap / Allied Chambers. Previously: The Wordsworth Dictionary of Science and Technology. W. R. Chambers / Cambridge U. Pr. 1998.
  4. ^ Cohen, R.; Burger, Y.; Katzir, N. (2004). "Monitoring Physiological races of Podosphaera xanthii (syn. Sphaerotheca fuliginea), the Causal Agent of Powdery Mildew in Curcubits: Factors Affecting Race Identification and the Importance for Research and Commerce". Phythoparasitica. 32 (2): 174–183. doi:10.1007/bf02979784. S2CID 27174422.