DIVISION II. RULES AND RECOMMENDATIONS
CHAPTER IV. EFFECTIVE AND VALID PUBLICATION
SECTION 4. GENERAL RECOMMENDATIONS ON CITATION
In the citation of a name that is not validly published because it was merely cited as a synonym, the words "as synonym" or "pro syn." should be added.
50B.1. In the citation of a nomen nudum, its status should be indicated by adding the words "nomen nudum" or "nom. nud."
Ex. 1. "Carex bebbii" (Olney, Car. Bor.-Am. 2: 12. 1871), published without a description or diagnosis, should be cited as
Carex bebbii Olney, nomen nudum (or nom. nud.).
50C.1. The citation of a later homonym should be followed by the name of the author of
the earlier homonym preceded by the word "non", preferably with the date of publication added. In some instances it will be advisable to cite also any other homonyms, preceded by the word "nec".
Ex. 1. Ulmus racemosa Thomas in Amer. J. Sci. Arts 19: 170. 1831, non Borkh. 1800.
Ex. 2. Lindera Thunb., Nov. Gen. Pl.: 64. 1783, non Adans. 1763.
Ex. 3. Bartlingia Brongn. in Ann. Sci. Nat. (Paris) 10: 373. 1827, non Rchb. 1824 nec F. Muell. 1882.
50D.1. Misidentifications should not be included in synonymies but added after them. A misapplied name should be indicated by the words "auct. non" followed by the name of the original author and the bibliographic reference of the misidentification.
Ex. 1. Ficus stortophylla Warb. in Ann. Mus. Congo Belge, Bot., ser. 4, 1: 32. 1904.
F. irumuënsis De Wild., Pl. Bequaert. 1: 341. 1922. "F. exasperata" auct. non Vahl: De Wildeman & Durand in Ann. Mus. Congo Belge, Bot., ser. 2, 1: 54. 1899; De Wildeman, Miss. Em. Laurent: 26. 1905; Durand & Durand, Syll. Fl. Congol.: 505. 1909.
50E.1. If a name of a family, genus, or species is accepted as a nomen conservandum (see
Art. 14 and App.
II-IV) the abbreviation "nom. cons." or, in the case of a conserved spelling, “orth. cons.” should be added in a formal citation.
Ex. 1. Protea L., Mant. Pl.: 187. 1771, nom. cons., non L. 1753.
Ex. 2. Combretum Loefl. 1758, nom. cons. [= Grislea L. 1753].
Ex. 3. Glechoma L. 1753, orth. cons., ‘Glecoma’.
If a name has been rejected and has been placed on the list of nomina utique
rejicienda (see Art. 56 and App. V) the abbreviation “nom. rej.” should be added in a formal citation.
Ex. 4. Betula alba
L. 1753, nom. rej.
Rec. 50E.2 also applies to any combination based on a nomen utique rejiciendum (see Art. 56.1
Ex. 5. Dryobalanops sumatrensis
(J. F. Gmel.) Kosterm. in Blumea 33: 346. 1988, nom. rej.
50E.3. If a name has been adopted by Fries or Persoon, and thereby sanctioned (see
Art. 13.1(d) and 7.8), ": Fr." or ": Pers." should be added in a formal citation. The same convention should be used for the basionym of the sanctioned name, if it has one, and for all combinations based on either the sanctioned name or its basionym.
Ex. 6. Boletus piperatus Bull. (Herb. France: t. 451, f. 2. 1790) was accepted in Fries (Syst. Mycol. 1: 388. 1821) and was thereby sanctioned. It should thus be cited as
B. piperatus Bull. : Fr., and a subsequent combination based on it, as Chalciporus piperatus (Bull. : Fr.) Bataille.
Ex. 7. Agaricus sarcocephalus Fr. 1815 : Fr. was sanctioned as
Agaricus compactus [unranked] sarcocephalus (Fr. : Fr.) Fr. 1821;
Psathyrella sarcocephala (Fr. : Fr.) Singer is a subsequent combination based on it.
50F.1. If a name is cited with alterations from the form as originally published, it is desirable that in full citations the exact original form should be added, preferably between single or double quotation marks.
Ex. 1. Pyrus calleryana Decne. (P. mairei H. Lév. in Repert. Spec. Nov. Regni Veg. 12: 189. 1913,
Ex. 2. Zanthoxylum cribrosum Spreng., Syst. Veg. 1: 946. 1825,
"Xanthoxylon". (Z. caribaeum var. floridanum (Nutt.) A. Gray in Proc. Amer. Acad. Arts 23: 225. 1888,
Ex. 3. Spathiphyllum solomonense Nicolson in Amer. J. Bot. 54: 496. 1967,
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