Article 31

31.1. The date of effective publication is the date on which the printed matter became available as defined in Art. 29 and 30. In the absence of proof establishing some other date, the one appearing in the printed matter must be accepted as correct.

Ex. 1. Individual parts of Willdenow's Species plantarum were published as follows: 1(1), Jun 1797; 1(2), Jul 1798; 2(1), Mar 1799; 2(2), Dec 1799; 3(1), 1800; 3(2), Nov 1802; 3(3), Apr-Dec 1803; 4(1), 1805; 4(2), 1806; these dates are presently accepted as the dates of effective publication (see Stafleu & Cowan in Regnum Veg. 116: 303. 1988).
Ex. 2. T. M. Fries first published Lichenes arctoi in 1860 as an independently paginated preprint, which predates the identical version published in a journal (Nova Acta Reg. Soc. Sci. Upsal. ser. 3, 3: 103-398. 1861).
Ex. 3. Diatom Research, vol. 2, no. 2, bears a title-page date of Dec 1987, but the authors of a paper included in a later issue (vol. 3, p. 265) stated that the date of publication was 18 Feb 1988, which therefore should be taken as the date of all nomenclatural novelties in that issue of the journal.
Note 1. Effective publication requires distribution of printed matter, which establishes the date of effective publication, even if a name is published in a periodical with parallel printed and electronic versions.
Ex. 4. The paper in which the name Ceratocystis omanensis Al-Subhi & al. is described was available online in final form on Science Direct on 7 November 2005, and distributed in a printed version in Mycological Research 110(2): 237-245 on 7 March 2006. The date of effective publication of the name for the purposes of this Article is 7 March 2006 and not 7 November 2005.

31.2. When separates from periodicals or other works placed on sale are issued in advance, the date on the separate is accepted as the date of effective publication unless there is evidence that it is erroneous.

Ex. 5. The names of the Selaginella species published by Hieronymus (in Hedwigia 51: 241-272) were effectively published on 15 October 1911, since the volume in which the paper appeared, though dated 1912, states (p. ii) that the separate appeared on that date.

Recommendation 31A

31A.1. The date on which the publisher or publisher's agent delivers printed matter to one of the usual carriers for distribution to the public should be accepted as its date of effective publication.


(c) 2006, by International Association for Plant Taxonomy. This page last updated  13.03.2007 .