Resolving some nomenclatural issues on Isoeto-Nanojuncetea and four new communities of the Iberian Peninsula

. We describe four new vegetation units and propose 17 new typifications and 24 altered names of syntaxa belonging to Isoeto-Nanojuncetea . Information is also provided on the publication dates of the alliances Isoetion and Preslion


Introduction and Methods
We have been working on Isoeto-Nanojuncetea Br.-Bl. & Tüxen in Br.-Bl. et al. 1952, mainly in the Iberian Peninsula and northern Morocco, over the past 20 years (Molina & Casado, 1997;Espírito-Santo & Arsénio, 2005;Molina, 2005;Molina et al., 2009;Pinto-Cruz et al., 2009;Silva et al., 2009aSilva et al., , 2009b. Some new communities were described and others confirmed for the Iberian territory (Silva et al., 2008(Silva et al., , 2009cCosta et al., 2012). Plant communities of temporary ponds compose a highly specialized vegetation with an extremely patchy distribution that poses challenges for classification (e.g. Silva, 2009). Nevertheless, syntaxa belonging to this class have been described from the beginnings of phytosociology almost a century ago, often using obsolete name-giving taxa that make more complicate the nomenclatural interpretations of the units (e.g. Braun-Blanquet, 1922, 1936a. Here we describe three new associations and one new subassociation, designate 17 type relevés and propose the correction, completion or mutation of 24 names following the rules of the 4th edition of the International Code of Phytosociological Nomenclature (ICPN; Theurillat et al., 2020). The nomenclature of vascular plants follows Flora iberica (Castroviejo, 1986(Castroviejo, -2019, and for families not yet published in this flora we followed Euro+Med (2006-), except for Isoetes delilei, which agrees with Greuter & Troia (2015), and Isoetes longissima with Troia & Greuter (2014).

Publication dates of the alliances Isoetion and Preslion cervinae
The name Isoetion was invalidly published by Braun-Blanquet (1931: 39) because a sufficient original diagnosis was not provided (ICPN, Art. 2b). Thereafter, the author provided a sufficient diagnosis validating the alliance name in the paper Un joyau floristique et phytosociologique "L'Isoetion" méditerranéen, that was published in the Bulletin de la Société d'Étude des Sciences Naturelles de Nîmes (Braun-Blanquet, 1936a) and also in a Communication of the SIGMA (Braun-Blanquet, 1936b). Text and page makeup are identical in both publications, except for the page numbering. The Communication is dated on the cover page in January 1936 and contains a reference to the Bulletin on the last page: "Extrait du Bulletin de la Société d'Etude des Sciences Naturelles de Nîmes, t. XLVII, 1930-35". An PHYTOSOCIOLOGICAL NOMENCLATURE SECTION additional evidence that the Communication should be considered as a reprint of the Bulletin is that in both publications a reference to the 'Communication nº 40' is indicated in the first page under the title, but the Communication published is the number 42 of the series, suggesting that it was postponed until the Bulletin was published. The precise date of publication of volume 47 of the Bulletin is unknown, but on page 252 there is a reference to a meeting of the Société held on November 29, 1935. Hence, it is highly unlikely that the volume could have been published before 1936 (D. Kania, pers. comm.). The author citation should therefore be Isoetion Braun-Blanquet 1936, as indicated by Theurillat et al. (2020).

Eryngio corniculati-Isoetetum delilei
The correct name-giving taxon is not Isoetes setacea but Isoetes delilei Rothm. (Greuter & Troia, 2015). In corrections according to Art. 44 the author and the year of the correction are not indicated. Brullo & Minissale 1998 Syn. The association 'Hyperico-Cicendietum filiformis Rivas Goday (1964) 1970' is based on the previous name 'Cicendietum filiformis (Allorge 1922) salmantico y onubense' (Rivas Goday, 1964: 222), which must be considered invalid as the rank indicated for it was 'regional variants' ['variantes regionales'] (Art. 3d). The name Hyperico-Cicendietum filiformis Rivas Goday 1970 was validly proposed by Rivas Goday (1970: 239), but the name-giving taxon indicated was Hypericum humifusum subsp. australe (Ten.) Rouy & Fouc., which is an illegitimate synonym of H. australe Ten. Although H. humifusum was the only species indicated in the original relevés of Rivas Goday (1964: 222), we can conclude that Rivas Goday (1970) subsequently assumed that the taxon they contained corresponded to H. humifusum subsp. australe (Rivas Goday, 1970: 226, 231, 239). According to Flora iberica (Castroviejo, 1986(Castroviejo, -2019 this taxon is not present in the area from which the association was described, and the name completed according to the original diagnosis and Art. 10a Note 2 (Hyperico australis-Cicendietum) is therefore an inadequate name that cannot be used (Art. 43, nomen ineptum). Although the name 'Hyperico humifusi-Cicendietum filiformis Rivas Goday 1970' has been cited in several publications Costa et al., 2012;De Foucault, 2013a;Gigante et al., 2013), Rivas Goday's name has still not been formally corrected. The correction of this name according to Art. 43 would also create an illegitimate later homonym (Art. 31) of the name Hyperico humifusi-Cicendietum filiformis Brullo & Minissale 1998(Brullo & Minissale, 1998. This latter name, based on relevés from the province of Zamora (Navarro & Valle, 1984), is a syntaxonomic synonym and in fact the name that must be used for the association. This Carpetan-Leonese and Oroiberian syntaxon was originally assigned to Cicendion (Rivas Martínez, 1964, 1981, a position also accepted by Jansen & Sequeira (1999) for Serra da Estrela. It was subsequently subordinated to the alliance Menthion cervinae Costa et al., 2012), which is typical of sites with a higher flooding level. According to the original diagnosis and its Iberian-Atlantic character, it seems more appropriate to reassign it to Cicendion.

Myosuro minimi-Crassuletum vaillantii
De Foucault (2013b: 90) designated a lectotype for the name 'Myosuro-Bulliardetum vaillantii Br.-Bl. 1936', but this lectotypification is superfluous because the name is invalid (Art. 19c). The original diagnosis (Braun-Blanquet et al., 1952) includes a reference to Braun-Blanquet (1936a) and provides a synoptic table that exactly matches the four relevés published by Braun-Blanquet in 1936. The relevé we selected as type is therefore part of the original diagnosis and must be considered as a lectotype. Agrostis pourretii Willd. is the correct name in the genus Agrostis for Agrostis salmantica (Lag.) Kunth, hence the association name must be corrected according to Art. 44 of the ICPN. Rivas-Martínez et al. (2002) formerly proposed this correction. The lectotypification proposed by Belmonte (1986: 48) was not effectively published (Art. 1). This association was firstly published in Rivas Goday (1968: 1022-1023) with a sufficient original diagnosis including a synoptic table. Thereafter, Pérez Latorre et al. (1999) designated the neotype indicating that the taxon present in the association corresponds to Juncus hybridus Brot., but do not corrected the association name. Indeed, the namegiving taxon Juncus tingitanus Maire & Weiller is absent from the area (Cádiz province) where the association was described (Castroviejo, 1986(Castroviejo, -2019Romero Zarco, 2010). Silva et al. (2008) formerly proposed the correction of this name to Laurentio michelii-Juncetum hybridi (Art. 43).

Cypero micheliani-Crypsietum alopecuroidis
Since Heleochloa alopecuroides is currently included in the genus Crypsis as Crypsis alopecuroides (Tutin et al., 1980;Euro+Med, 2006-), the name of the association may be mutated (Art. 45). Rivas-Martínez et al. (2002: 256) already proposed the mutation. Although several Cyperus species are indicated in the original diagnosis, only C. michelianus (the more frequent and abundant) is considered as character species of the association by the authors. The original name-giving taxon is Fimbristylis dichotoma, a misapplied name for F. bisumbellata in southern Spain (Castroviejo, 1986(Castroviejo, -2019. Brullo & Minissale (1998) formerly proposed the correction of this association name, which corresponds to Art. 44. The first name-giving taxon Panicum debile is currently treated as a synonym of Digitaria debilis (Tutin et al., 1980;Euro+Med, 2006-), and the name needs to be mutated (Art. 45).  (Bolòs, 1979: 202).