Report 3 of the Committee for Change and Conservation of Names (CCCN)

Abstract

We report the decisions made by the Assembly of the Group of Phytosociological Nomenclature (GPN) in 2023 on previous recommendations of the Committee for Change and Conservation of Names (CCCN). Further, we discuss eight Requests for a binding decision and nine nomenclatural Proposals. Recommendations on acceptance or rejection of these Proposals are provided. We recommend the conservation of the following names: Mesobromion erecti (Braun-Blanquet et Moor 1938) Zoller 1954, Galio sylvatici-Carpinetum betuli Oberdorfer 1957, Lithospermo-Carpinetum betuli Oberdorfer 1957, Nanocyperetalia Klika 1935, Isoetetalia Braun-Blanquet 1936 and Molinio arundinaceae-Quercetum Neuhäusl et Neuhäuslová-Novotná 1967.

Abbreviations : CCCN = Committee for Change and Conservation of Names; GPN = Working Group for Phytosociological Nomenclature; ICPN = International Code of Phytosociological Nomenclature; VCS = Vegetation Classification and Survey.

Introduction

The Committee for Change and Conservation of Names (CCCN) is a Topic Committee of the Working Group for Phytosociological Nomenclature (GPN) established in accordance with the International Code of Phytosociological Nomenclature (ICPN; Theurillat et al. 2021). Its task is to evaluate requests for binding decisions on controversial or ambiguous cases in the interpretation of the Code, and proposals for the conservation or rejection of syntaxon names. In the last report of the Committee (Willner et al. 2021) we announced the next one for the year 2022. However, as usual, most of the nomenclatural cases turned out to be quite complicated, and the progress of our discussions was slower than expected. In fact, several Proposals touched on very fundamental questions of interpretation of the ICPN, and some of them also revealed ambiguities that should be addressed in the next edition of the Code. This, together with the other obligations of each committee member, led to a delay of two years. Nevertheless, we are pleased to present the third Report of the CCCN .

In May 2022, the GPN Steering Committee co-opted Massimo Terzi to the CCCN . It now consists of six members, namely: Wolfgang Willner (chair), Andraž Čarni, Federico Fernández-González, Jens Pallas, Massimo Terzi and Jean-Paul Theurillat.

Authors wishing to submit a Proposal or a Request for a binding decision on a syntaxon name are asked to consult Appendices 2 and 6 of the International Code of Phytosociological Nomenclature (ICPN), respectively (Theurillat et al. 2021). It is highly recommended to consult previously published Proposals and Requests. All Proposals and Requests published in Vegetation Classification and Survey (VCS) are automatically processed by the CCCN according to the ICPN rules. Concerning the submission itself, there are two possibilities. Proposals and Requests can be submitted as independent articles using the VCS submission system. In this case, article processing charges may apply, depending on your country and status. Alternatively, you can submit a Proposal or a Request with the same structure by e-mail to the first author of this report. In the latter case, the Proposals and the Requests will be published in the next CCCN Report (the authors of each Proposal will be indicated). Publication of nomenclatural Proposals and Requests as part of the CCCN Report is free of charge.

Our report is structured into three main sections: In the first section, we report the final decisions made by the GPN Assembly on previous recommendations of the CCCN . In the second section, we discuss new Requests for binding decisions, and in the third one, we discuss new Proposals for the conservation or rejection of syntaxon names. Our recommendations remain provisional until approved by the GPN Assembly. The final decisions on the new recommendations will be presented in the next CCCN Report.

Decisions by the GPN Assembly

In spring 2023, the members of the GPN were asked to vote on the recommendations published in the last CCCN Report (Willner et al. 2021). The voting was done per e-mail and took place from 10 March to 10 April 2023. Members were asked whether they agreed or disagreed with the CCCN recommendations. The results were as follows [an asterisk (*) after the proposal number indicates that the recommended version of the proposal differs from the original one]:

(17*) To conserve the name Berberidion Braun-Blanquet 1950 with a conserved type and against Prunion spinosae Soó 1931 (recommended). Vote: 22 yes, 0 no.

(20) To conserve the name Aceretalia pseudoplatani Moor 1976 against Tilietalia Moor 1973 (recommended). Vote: 23 yes, 0 no.

(21) To conserve the name Festucetalia valesiacae Br.-Bl. et Tx. ex Br.-Bl. 1950 against Festucetalia Soó 1940 (not recommended). Vote: 12 yes, 6 no.

(21*) To conserve the name Festucetalia valesiacae Br.-Bl. et Tx. ex Br.-Bl. 1950 with a conserved type and against Festucetalia Soó 1940 (recommended). Vote: 21 yes, 0 no.

All recommendations (positive and negative ones) have been accepted. Therefore, the following entries are to be added to Appendix 3 of the ICPN (Theurillat et al. 2021):

(17) Berberidion Braun-Blanquet 1950 nom. et typus cons. [ Braun-Blanquet 1948–1950, part 6: 349]

(=) Prunion spinosae Soó 1931 [ Soó 1931 : 294]

Typus conservandus: Berberido-Rosetum Braun-Blanquet 1961 [ Braun-Blanquet 1961 : 189].

(20) Aceretalia pseudoplatani Moor 1976 nom. cons. [ Moor 1976 : 330, 336]

(=) Tilietalia Moor 1973 [ Moor 1973 : 128–129]

Holotypus: Lunario-Acerion Moor 1973 [ Moor 1973 : 128]

(21) Festucetalia valesiacae Braun-Blanquet et Tüxen ex Braun-Blanquet 1950 nom. et typus cons. [ Braun-Blanquet 1948–1950, part 3: 312]

(=) Festucetalia Soó 1940 [ Soó 1940 : 32]

Typus conservandus: Festucion valesiacae Klika 1931 [ Klika 1931 : 376]

Recommendations on Requests for a binding decision

During the reporting period, the CCCN examined four published Requests for a binding decision. They are numbered from (1) to (4) in the following section, as in the original publications. In addition, several ad hoc Requests arose during the discussion of Proposals. These are numbered (A1), (A2), etc., in the order in which they were discussed.

(1) Name-giving taxon in the name Isoeto longissimae-Cicendietum Br.-Bl. 1967 nom. corr. Request by Silva and Molina (2021) . Suggested completion of the name: Isoeto longissimae-Cicendietum filiformis . Vote: 6 pro, 0 contra (recommended).

The members of the CCCN see no problem with the proposed choice of the name-giving Cicendia species and therefore recommend that the Request be accepted. However, we noticed that the nomenclature of the corresponding alliance ‘ Cicendion (Rivas Goday in Rivas Goday et Borja 1961) Br.-Bl. 1967’ (form of the name in Mucina et al. 2016) needs a thorough revision, which will be published elsewhere.

(2) Name-giving taxon in the name Gnaphalio-Verbenetum supinae Rivas Goday 1970 nom. invers. Request by Silva and Molina (2021) . Suggested completion of the name: Gnaphalio luteoalbi-Verbenetum supinae . Vote: 6 pro, 0 contra (recommended).

While the CCCN supports the proposed name-giving Gnaphalium species, there was a discussion about the legitimacy of the inversion of the name. Both Gnaphalium luteoalbum and Verbena supina belong to the herb layer, so only the second paragraph of Art. 10b applies. The inversion is based on the lectotype where Verbena supina has a higher cover than Gnaphalium luteoalbum . However, considering the original diagnosis as a whole (table 8 in Rivas Goday 1970), G. luteoalbum has a higher cover in six out of ten relevés, V. supina has a higher cover in three relevés, and in one relevé both species have the same cover. While Art. 42 clearly states that the nomenclatural type is relevant to determine the correct order sequence of the name-giving taxa, there is no reference to the type in Art. 10b. This creates some ambiguity that should be addressed in the next edition of the Code.

(3) Valid publication of the names Xerobromion and Mesobromion in Zoller 1954 . Request by Terzi et al. (2021) . Recommendation: Both names are valid (6 pro, 0 contra).

Braun-Blanquet and Moor (1938) proposed the two suballiances Xerobromenion and Mesobromenion within the alliance Bromion Koch 1926 to separate the xerophilous associations from the meso-xerophilous ones. At that time, however, the same termination - ion was used for both the alliance and the suballiance rank (i.e., Xerobromion and Mesobromion, respectively). Thus, the use of the names without an explicit indication of the rank was ambiguous. Zoller (1954) adopted the names Xerobromion and Mesobromion, stating that these two units were so different from each other that they could only be united under a single alliance Bromion by force (“mit Zwang”; Zoller 1954, p. 36), and therefore such a concept was not followed in his work. However, this rejection of the alliance Bromion alone can not by itself be accepted as a valid change of rank of the previously published suballiances, also because Zoller mentioned “characteristic species of the suballiance Xerobromion ” in two tables. Fortunately, the new rank is explicitly mentioned at a few places (“ Xerobromion -Verband”: p. 50, p. 52; “ Mesobromion -Verband”: p. 253), a fact that was only discovered after the publication of the Request. Therefore, it is clear that the names Xerobromion (Braun-Blanquet et Moor 1938) Zoller 1954 and Mesobromion (Braun-Blanquet et Moor 1938) Zoller 1954 can be accepted as validly published.

The requirement of explicitly using the name at the new rank – in this case with the explicit indication of the rank, as the termination - ion is ambiguous – is analogous to the rule for changing the position of a subassociation (Art. 4b): the new combination (association name plus subassociation epithet) must be used explicitly; the mere expression of the change of position is not sufficient.

(A1) Valid publication of the names Carpinetum and Alno-Carpinetum in Issler 1924 . Request by W. Willner (CCCN). Recommendation: Both names are valid (4 pro, 1 contra, 1 abstention).

During the discussion of Proposals 24 and 25 (Novák 2019, see below) it became necessary to decide on the validity of the association names published by Issler (1924) in the first part of his study of the forests of the southern Vosges mountains and the adjacent Rhine plain. In the original Proposals (Novák 2019), the names Carpinetum and Alno-Carpinetum were considered as not validly published in Issler (1924), because the diagnoses consist only of synoptic species lists, where for each species a range of cover values found in the individual relevés is given. However, the majority of the CCCN members concluded that this is a sufficient diagnosis in the sense of Art. 7, as it can be seen as an indication of mean cover values.

(A2) Name-giving taxon in the name Lithospermo-Carpinetum betuli Oberdorfer 1957 . Request by Novák (2019) . Suggested completion of the name: Lithospermo purpurocaerulei-Carpinetum betuli Oberdorfer 1957 . Vote: 6 pro, 0 contra (recommended).

This Request was part of Proposal 24 (see below). Lithospermum purpurocaeruleum is mentioned as a character species of the association with constancy IV, while L. officinale is listed as a class species with constancy II. Although L. purpurocaeruleum may have been intended as the name-giving taxon, there is no information in the original diagnosis that this was the case. The CCCN voted unanimously to accept the choice of L. purpurocaeruleum as the name-giving species.

(A3) Name-giving taxon in the name Nanocyperetalia Klika 1935. Request by J.-P. Theurillat (CCCN). Suggested completion of the name: Nanocyperetalia flavescentis . Vote: 5 pro, 1 abstention (recommended).

The holotype of this order is the alliance Nanocyperion flavescentis Koch 1926 [see Proposal 26 (Fernández-González et al. 2021) for details]. However, while the name-giving taxon of the alliance is clear, because the specific epithet was added in the original diagnosis, this is not the case for the order name, which was published without epithet. As there is more than one Cyperus species present in the original diagnosis of the alliance (and therefore the order), a binding decision must be made. We propose to select the same name-giving taxon as for the alliance, namely Cyperus flavescens L. (Sp. Pl. 1: 46. 1753).

(A4) Name-giving taxa in the names Isoetetalia Braun-Blanquet 1936 and Isoetion Braun-Blanquet 1936 . Request by J.-P. Theurillat (CCCN). Suggested completion of the names: Isoetetalia durieui and Isoetion durieui . Vote: 5 pro, 1 abstention (recommended).

Both names were published without a specific epithet and are mostly used without epithet in the literature. However, since the type association of the Isoetion is the Isoetetum durieui Braun-Blanquet 1936 (Brullo and Minissale 1998), we propose Isoetes durieui Bory 1844 as the name-giving taxon of both the alliance and order names. See also Proposal 27 (Fernández-González et al. 2021) below.

(4) Name-giving taxon in the names Molinio arundinaceae-Quercetum Samek 1962 and Molinio arundinaceae-Quercetum Neuhäusl et Neuhäuslová-Novotná 1967. Request by Slezák et al. (2021) . Suggested completion of the names: Molinio arundinaceae-Quercetum roboris . Vote: 5 pro, 1 abstention (recommended).

This request was submitted together with Proposal 28 (Slezák et al. 2021, see below). The two names in question refer to hygrophytic oak forests where the dominant oak species is usually Quercus robur (Roleček 2013). The CCCN recommends accepting the choice of Q. robur as the name-giving species in both association names.

Recommendations on published Proposals

The Proposals are numbered as in the original publication. An asterisk (*) after the number of the Proposal indicates that the recommended version of the Proposal differs from the original one.

(22) To conserve the name Mesobromion erecti (Braun-Blanquet et Moor 1938) Oberdorfer 1957 against the name Bromion erecti Koch 1926 . Proposed by Theurillat et al. (2017) . Following the conclusions on Request 3 for a binding decision on the validity of the alliance name Mesobromion erecti published in Zoller (1954) (see above), the Proposal was modified accordingly (see Proposal 22*). No vote.

(22*) To conserve the name Mesobromion erecti (Braun-Blanquet et Moor 1938) Zoller 1954 against the name Bromion erecti Koch 1926 . Modified version of the Proposal by Theurillat et al. (2017) . Vote: 3 pro, 2 contra, 1 abstention (recommended).

Although the CCCN did not reach a unanimous decision, a majority voted in favour of this Proposal. The main reasons are as follows: (i) The name Bromion erecti is potentially confusing for people unfamiliar with phytosociological nomenclature. Mesobromion and Xerobromion are names with well-defined contents, whereas Bromion has been used in at least three different ways: (a) in the sense of the Mesobromion (e.g., Mucina et al. 1993, 2016; Chytrý 2007), (b) in the sense of the Xerobromion (Oberdorfer 1957; Korneck 1974) and (c) for a unit comprising both (Braun-Blanquet and Moor 1938; Braun-Blanquet 1948–1950). (ii) Braun-Blanquet and Moor (1938) clearly considered the Xerobromion as the typical core of the Bromion . As noted by Zoller (1954), about half of the alliance character species listed by Braun-Blanquet and Moor are more or less restricted to the Xerobromion . Therefore, the decision of Oberdorfer (1957) to maintain the name Bromion for the Xerobromion is completely understandable from a historical point of view, although not in accordance with the ICPN (which had not yet been published in 1957). (iii) For a long period, the name Bromion was not in common use. It was restored when authors started to follow the ICPN and realised that the type of the name Bromion was the Mesobrometum erecti Koch 1926 . However, conservation of names was not possible at that time. Nevertheless, several authors continued to use the name Mesobromion instead of Bromion (Weeda et al. 2002; Aeschimann et al. 2004; Bardat et al. 2004; Delarze et al. 2015; Willner et al. 2019).

There was also a lively discussion in the CCCN about the type of the name Mesobromion erecti (Braun-Blanquet et Moor 1938) Zoller 1954 . The Mesobrometum erecti was validly published for the first time in Koch (1926) . However, because of the absence of complete bibliographic references in Braun-Blanquet and Moor (1938), Theurillat et al. (2017) concluded that the type of the basionym Mesobromenion erecti Braun-Blanquet et Moor 1938 is a later homonym of Koch’s name, the ‘ Mesobrometum erecti Scherrer ex Braun-Blanquet et Moor 1938’. In the meantime, further considerations led to the conclusion that the volumes of the Prodrome of Plant Communities (Prodromus der Pflanzengesellschaften, Prodrome des groupements végétaux) published between 1933 and 1940, of which Braun-Blanquet and Moor (1938) is the 5^th part, should be considered as a single work, including the Bibliographia Phytosociologica (Tüxen and Prügel 1935; De Leeuw 1935; Braun-Blanquet and Diemont 1936). A reference to the published volumes of the Bibliographia is given on the back cover of each volume of the Prodrome, and a generic reference is also given in the first volume (Braun-Blanquet 1933 : 4). Thus, the name Mesobrometum in Braun-Blanquet and Moor (1938) is not a later homonym, because there is a sufficient indirect reference to Koch (1926) : on p. 40 and 41, under the Mesobrometum typicum, Braun-Blanquet and Moor (1938) refer to Tüxen (1928), and the full bibliographical details can be found in the Bibliographia Phytosociologica, Fasc. 1 (Tüxen and Prügel 1935). Tüxen (1928), describing the Mesobrometum of NW Germany, provided an unambiguous reference to Koch (1926) .

Another question is the correct author citation of the Mesobrometum erecti . Koch (1926) referred the name to “Braun-Blanquet, Max Scherrer”. As shown by Terzi et al. (2016), the (invalid) subass. “ Brometum bromosum ” of Scherrer (1925) is part of the original diagnosis of Koch’s Mesobrometum . According to Scherrer (1925), Braun-Blanquet suggested the name “ Meso-Brometum ” for this mesophilous type of the Brometum, but this name was not definitely adopted by Scherrer. Moreover, Scherrer provided unambiguous references to the Xero-Brometum, which he considered as another subassociation of the Brometum . However, by using the name Mesobrometum, Koch clearly excluded the Xero-Brometum from his association. One could say that Koch raised Scherrer’s invalid subassociation ‘ Brometum bromosum ’ to the rank of association. However, as the name Mesobrometum was proposed by Braun-Blanquet, and not by Scherrer, it is recommended to cite the name as Mesobrometum Braun-Blanquet ex Koch 1926, and not as Mesobrometum Scherrer ex Koch 1926, but Mesobrometum Braun-Blanquet et Scherrer ex Koch 1926 could be an alternative. This is, in fact, a matter of taste and has no nomenclatural consequences.

(23) To conserve the name Galio sylvatici-Carpinetum betuli Oberdorfer 1957 against Querco pedunculatae-Carpinetum betuli Klika 1928 . Proposed by Novák (2019) . Vote: 5 pro, 1 contra (recommended).

The name Galio sylvatici-Carpinetum betuli is widely used for the oak-hornbeam forests of Central Europe, except in the more Atlantic west, where the name-giving Galium sylvaticum and some other diagnostic species do not occur and the Galio-Carpinetum is replaced by the Stellario-Carpinetum (Oberdorfer 1992; Leuschner and Ellenberg 2017). Some authors (e.g., Willner and Grabherr 2007; Novák et al. 2020) exclude the moist oak-hornbeam forests from the Galio-Carpinetum and include them in a broader Stellario-Carpinetum (see also Proposal 25). Regardless of this syntaxonomic question, all authors agree that the typical Galio-Carpinetum occurs on relatively dry soils, and that the co-dominant oak species on such sites is usually Quercus petraea . Before 1957, all the oak-hornbeam forests of Central Europe were grouped into a single broad association Querco-Carpinetum, but this name has not been used in any major reference work for decades.

The first author who described a Querco-Carpinetum was Klika (1928) . In fact, Klika (1928, p. 34ff) described two associations of oak-hornbeam forests: a ‘ Quercetum pedunculatae-Carpinetum ’ on drier soils and a ‘ Carpinetum ’ on more mesic soils. While the latter is an illegitimate homonym of the Carpinetum Issler 1924 (see also Proposal 24*), the ‘ Quercetum pedunculatae-Carpinetum ’ (recte: Querco roboris-Carpinetum nom. corr.) is a legitimate name that would have priority over the name Galio sylvatici-Carpinetum Oberdorfer 1957 . As mentioned above, the co-dominance of Quercus robur is rather atypical for dry oak-hornbeam forests, and Klika (1928) even says that it is probably a result of forestry. Thus, the name Querco roboris-Carpinetum Klika 1928 nom. corr. would not only replace a well-established name in current use, but would also be misleading with regard to the natural tree species composition of this community. Moreover, another Querco roboris-Carpinetum was described independently of Klika by Tüxen (1930) . However, the ‘ Querceto-Carpinetum ’ [recte: Querco roboris-Carpinetum ] Tüxen 1930 corresponds syntaxonomically to the Stellario-Carpinetum Oberdorfer 1957 (see, e.g., Preising et al. 2003). Although both Q. robur and Q. petraea are present in the original diagnosis of Tüxen’s name (with Q. robur being by far the more frequent one), the ‘ Querceto-Carpinetum ’ is in fact a later homonym to Klika’s ‘ Quercetum pedunculatae-Carpinetum ’ because on the first page of his paper, Tüxen (1930) writes “Assoziation von Quercus robur und Carpinus betulus = Querceto-Carpinetum ”. So it is clear that Q. robur is the name-giving oak species in Tüxen’s ‘ Querceto-Carpinetum ’.

In view of all these facts, it is obvious that the reintroduction of the name Querco roboris-Carpinetum Klika 1928 nom. corr. would be a continuous source of error, and the conservation of the name Galio sylvatici-Carpinetum Oberdorfer 1957 is recommended.

(24) To conserve the name Lithospermo-Carpinetum betuli Oberdorfer 1957 against Carpinetum betuli Issler 1925. Proposed by Novák (2019) . Following the conclusions on Request A1 for a binding decision (see above), the Proposal was modified accordingly (see Proposal 24*). No vote.

(24*) To conserve the name Lithospermo-Carpinetum betuli Oberdorfer 1957 against Carpinetum betuli Issler 1924 . Modified version of the Proposal by Novák (2019) . Vote: 4 pro, 1 contra, 1 abstention (recommended).

The Lithospermo-Carpinetum betuli Oberdorfer 1957 [or Lithospermo purpurocaerulei-Carpinetum betuli if Request A2 is accepted, see above] includes thermophytic oak-hornbeam forests in SW Central Europe (Boeuf et al. 2014; Novák et al. 2020). According to the principle of priority, the name Carpinetum betuli Issler 1924 should be adopted for this unit. However, this name has not been used in any major reference for almost a century. We therefore recommend that the Proposal be accepted.

Oberdorfer’s name Lithospermo-Carpinetum betuli is a nomen superfluum for the Carpinetum betuli Issler 1924 (Art. 29b), and is therefore automatically typified by Issler’s earlier name (Art. 18b). For the Carpinetum betuli Issler 1924, we select relevé 2 in table 3 in Issler (1926) as the neotypus hoc loco, which was the relevé proposed by Novák (2019) as the conserved type for the Lithospermo-Carpinetum . However, since the Carpinetum betuli Issler 1924 is validly published, no conserved type is necessary.

(25) To conserve the name Stellario holosteae-Carpinetum betuli Oberdorfer 1957 against Alno glutinosae-Carpinetum betuli Issler 1926 . Proposed by Novák (2019) . Following the conclusions on Request A1 for a binding decision (see above), the Proposal was modified accordingly (see Proposal 25*). No vote.

(25*) To conserve the name Stellario holosteae-Carpinetum betuli Oberdorfer 1957 against Alno glutinosae-Carpinetum betuli Issler 1924 . Modified version of the Proposal by Novák (2019) . Vote: 1 pro, 3 contra, 2 abstentions (not recommended).

The name Stellario-Carpinetum was coined by Oberdorfer (1957) for subatlantic oak-hornbeam forests lacking the diagnostic species of the more subcontinental Galio-Carpinetum (see Proposal 23). Oberdorfer (1957) distinguished five subassociations: typicum (on mesic sands), agrostietosum (on drier sands), and allietosum, ficarietosum and caricetosum brizoidis (all three on wet, gleyic soils). More recently, the Stellario-Carpinetum has been extended to include also the wet subassociations of the Galio-Carpinetum (e.g., Willner and Grabherr 2007; Chytrý 2013; Novák et al. 2020). However, the oldest name for wet oak-hornbeam forests in Central Europe is Alno glutinosae-Carpinetum Issler 1924 . This name has rarely been used in the Central European literature, but it was recently adopted by Boeuf et al. (2014) .

In contrast to Proposals 23 and 24, it can hardly be argued that the reintroduction of the name Alno-Carpinetum for wet oak-hornbeam forests would be a continuous source of error, even though it would be a change of a name commonly used in some countries. However, during the discussions in the CCCN, serious doubts arose as to whether the names Alno-Carpinetum Issler 1924 and Stellario-Carpinetum Oberdorfer 1957 really refer to the same association. As mentioned above, three of Oberdorfer’s subassociations are wet oak-hornbeam forests similar to the Alno-Carpinetum (although Oberdorfer did not mention this name), but the Stellario-Carpinetum typicum is not one of them. It is therefore possible that the Stellario-Carpinetum is actually the correct name for the Poo chaixii-Carpinetum sensu Novák et al. (2020), while the Stellario-Carpinetum sensu Novák et al. (2020) should be named Alno-Carpinetum . In conclusion, there was no majority in favour of the Proposal, and it is not recommended.

Since the original diagnosis of the Alno-Carpinetum only contains a synoptic table, we select a neotype from Issler (1926), i.e. from the relevés on which the synoptic list of Issler (1924) is based upon. We select relevé 3 in table 2 of Issler (1926) as the neotypus hoc loco of the Alno-Carpinetum Issler 1924 . This is the same relevé as the superfluous lectotype (Art. 19c) of the ‘ Alno-Carpinetum typicum Issler 1926 ’ selected by Boeuf et al. (2014, p. 158).

(26) To conserve the name Nanocyperetalia Klika 1935 against Nanocypero-Polygonetalia Koch 1926 . Proposed by Fernández-González et al. (2021) . Vote: 5 pro, 1 abstention (recommended).

The name Nanocypero-Polygonetalia Koch 1926, which to our knowledge has never been used since its first publication, was considered as invalid in Mucina et al. (2016) . However, as shown by Fernández-González et al. (2021), it is in fact valid and legitimate, thus threatening the well-established name Nanocyperetalia . This Proposal aims to avoid this inappropriate change of a commonly used name. The CCCN recommends its acceptance.

(27) To conserve the name Isoetetalia Braun-Blanquet 1936 with a conserved type. Proposed by Fernández-González et al. (2021) . Vote: 5 pro, 1 abstention (recommended).

According to its original diagnosis in Braun-Blanquet (1936), the name Isoetetalia is a superfluous name of the Nanocypero-Polygonetalia Koch 1926, since the order Isoetetalia includes the alliance Nanocyperion Koch 1926 in addition to the new alliance Isoetion . In the previous edition of the Code, it was not clear whether Art. 18b (ruling the type of superfluous names) would take precedence over Art. 20 in cases where the application of both articles leads to contradictory results. This has been clarified in the 4^th edition by explicitly stating that Art. 20 does not apply to superfluous names. Therefore, since the order Isoetetalia includes, in addition to the new alliance Isoetion, the alliance Nanocyperion Koch 1926, which is the type of the Nanocypero-Polygonetalia Koch 1926, the name Isoetetalia Braun-Blanquet 1936 is a superfluous name of the Nanocypero-Polygonetalia Koch 1926 and automatically gets the Nanocyperion flavescentis Koch 1926 as its type. Consequently, a new syntaxon name would be needed for the traditional concept of the Isoetetalia . To avoid such an inappropriate change of a commonly used name, Fernández-González et al. (2021) proposed to conserve the name Isoetetalia Braun-Blanquet 1936 with the Isoetion Braun-Blanquet 1936 as conserved type. The CCCN recommends that this Proposal be accepted.

(28) To conserve the name Molinio arundinaceae-Quercetum Neuhäusl et Neuhäuslová-Novotná 1967 against Molinio arundinaceae-Quercetum Samek 1962. Proposed by Slezák et al. (2021) . Vote: 5 pro, 1 abstention (recommended).

The name Molinio arundinaceae-Quercetum is used for hygrophytic Central European acidophilous oak forests (Pallas 1996; Moravec 1998; Valachovič et al. 2021). However, there are two independent homonyms, of which the earlier one (Molinio arundinaceae-Quercetum Samek 1962) is problematic because its type relevé does not fully fit the traditional concept of this association. To avoid the change of a commonly used name, Slezák et al. (2021) proposed to conserve the later homonym Molinio arundinaceae-Quercetum Neuhäusl et Neuhäuslová-Novotná 1967. The CCCN sees no problem with this Proposal and therefore recommends its acceptance. Moreover, a binding decision should be made to clarify the name-giving oak species in both names (see Request 4 above).

(29) To conserve the name Omphalodo nitidae-Coryletum avellanae Amigo, G. Azcárate et Romero 1994 with a conserved type. Proposed by Rodríguez-Guitián and Amigo Vázquez (2022). Vote: 2 pro, 4 contra (not recommended).

This name was coined by Amigo et al. (1994) for a mesophytic woodland community of the north-western Iberian Peninsula, mostly dominated by Corylus avellana, a tall shrub that occasionally reaches 10 m in height but is mostly confined to the (upper) shrub layer. However, the selected type relevé is dominated by the tree Quercus robur and, as stated by Rodríguez-Guitián and Amigo Vázquez (2022), represents “an oak forest [...], overshadowing an understory of Corylus avellana ”. Thus, the name Omphalodo nitidae-Coryletum avellanae is illegitimate because no name-giving taxon belongs to the highest of the dominant strata (Art. 29b). In the following years, the Omphalodo-Coryletum was interpreted as a seral community and accepted in syntaxonomic checklists of Spain and Portugal (Rivas-Martínez et al. 2001; Costa et al. 2012). The Proposal aims at preserving this current use of the name by means of a conserved type representing a hazel woodland without Quercus robur .

During the discussion of the Proposal, a contradiction between Art. 29b, Example 5 and Art. 53 was detected. On the one hand, the mentioned Example suggests that a name being illegitimate due to a physiognomically “untypical” type can be preserved by a conserved type. On the other hand, Art. 53 states that names rejected according to Art. 29b are not eligible for getting a conserved type. There was no agreement among the CCCN members whether this contradiction is absolute (and therefore could only be resolved by an amendment to the Code) or merely bad wording that could be resolved by appropriate interpretation (i.e., conservation is acceptable if the conserved type eliminates the violation of Art. 29b and at the same time preserves the current use of the name).

An important difference between the present Proposal and Example 5 of Art. 29b is the fact that the holotype of the Omphalodo nitidae-Coryletum avellanae was not selected by accident but fully intentionally. Indeed, Amigo et al. (1994) describe it as “one of our best examples of Omphalodo-Coryletum ”, and they classified the association within the alliance Carpinion betuli . This and the mentioned statement in Art. 53 led the majority of the CCCN to vote against the Proposal. A new name should be published for the hazel woodlands of the NW Iberian Peninsula.

(30) To conserve the name Polysticho setiferi-Fraxinetum excelsioris (Tüxen et Oberdorfer 1958) Rivas-Martínez ex Díaz et Fernández Prieto 1994 with a conserved type. Proposed by Loidi et al. (2022) . Vote: 2 pro, 3 contra, 1 abstention (not recommended).

This case is similar to the previous one in that it concerns the name of a woodland in the Atlantic part of the Iberian Peninsula, supposedly dominated by Quercus robur in its most mature stage, but more often represented by seral stages dominated by Fraxinus excelsior and Corylus avellana due to human land use. However, in contrast to the Omphalodo nitidae-Coryletum avellanae, the name-giving Fraxinus excelsior is a tree of similar size as Quercus robur . The name Polysticho setiferi-Fraxinetum excelsioris is a nomen novum for the illegitimate name Corylo-Fraxinetum cantabricum Tüxen et Oberdorfer 1958. However, in the lectotype selected by Díaz and Fernández Prieto (1994) Quercus robur (without layer) has only a +, Fraxinus excelsior (tree layer) a 2 and Fagus sylvatica (tree layer) a 4 (relevé 139 in table 87 in Tüxen and Oberdorfer 1958). Thus, although selected from the “typical” subassociation, the lectotype represents a transitional stand towards beech forests. Unfortunately, the second relevé of the typical subassociation is also problematic, as it is a shrubby stage dominated by Corylus avellana, having a tree layer cover of just 10% (“Kronenschluss 0.1”, with F. excelsior being the only species in the tree layer). Indeed, Tüxen and Oberdorfer (1958) wrote that the abundance of the tree species in both relevés was untypical, although they considered them to be relatively close to the “typus” of the association in terms of species composition. Moreover, they described relevé 139 as “ Fazies, die dem Fagetum nahesteht ” (facies close to the Fagetum). For the other relevé, they noted that it was “ durch Ausholzung etwas gestört ” (slightly disturbed by logging). In conclusion, both relevés do not correspond exactly to the named syntaxon in the author’s opinion, and they should not be selected as lectotype (Art. 19a).

Loidi et al. (2022) published a relevé strongly dominated by Quercus robur as neotype for the Polysticho setiferi-Fraxinetum excelsioris (≡ Corylo-Fraxinetum cantabricum) and, at the same time, they proposed this relevé as the conserved type. However, as shown above, the lectotypification by Díaz and Fernández Prieto (1994) must be rejected because the two relevés in the original diagnosis of the typical subassociation were considered atypical by the authors (Art. 19a, 21). Therefore, the establishment of a neotype was necessary, and the first publication of a neotype must be followed, unless it can be shown that it was based on a misinterpretation of the original diagnosis (Art. 21). Loidi et al. (2022) argue that it was due to the scarcity of forests dominated by Q. robur throughout the surveyed territory that Tüxen and Oberdorfer (1958) preferred to use Fraxinus excelsior as the name-giving tree species of the association instead of Quercus . However, a closer inspection of the original description gives a somewhat different picture. On p. 284, Tüxen and Oberdorfer (1958) write (translation from German): “Only ash (Fraxinus excelsior) and – in the shrub layer – hazel (Corylus avellana) occur constantly and often predominantly in all forms of this Atlantic forest community and are therefore best suited to denominate the association, especially as they differentiate it well against the oak-hornbeam forests of the Central European Querceto-Carpinetum . We did not use the oaks in the name because they (Quercus petraea and predominantly Quercus robur, but also Quercus pubescens and Quercus ilex) are not represented, let alone dominate, across the entire breadth of the association.“

Before proceeding to neotypification, the authors of the proposal should have considered whether forests dominated by Fraxinus excelsior and those dominated by Quercus robur could be considered as different associations, in which case a new association should be described for the latter, and a neotype with a dominance – or at least co-dominance – of F. excelsior in the tree layer should be selected for the former. However, this is a syntaxonomic question that is beyond the mandate of this Committee. In any case, there is no immediate need to conserve the name Polysticho setiferi-Fraxinetum excelsioris with a conserved type, and therefore the proposal is not recommended.

Data availability

No data used.

Author contributions

All authors are members of the CCCN and participated in the evaluation and discussion of the Proposals and the Requests. WW planned the report and wrote the first draft, which was commented and revised by all authors.

E-mail and ORCID

Wolfgang Willner (Corresponding author,[email protected]), ORCID:https://orcid.org/0000-0003-1591-8386

Andraž Čarni ([email protected]), ORCID:https://orcid.org/0000-0002-8909-4298

Federico Fernández-González ([email protected]), ORCID:https://orcid.org/0000-0003-1234-4065

Jens Pallas ([email protected])

Massimo Terzi ([email protected]), ORCID:https://orcid.org/0000-0001-8801-6733

Jean-Paul Theurillat ([email protected]), ORCID:https://orcid.org/0000-0002-1843-5809

References

Aeschimann D, Lauber K, Moser DM, Theurillat J-P (2004) Flora alpina. Haupt, Bern, CH.

Amigo J, Giménez de Azcárate J, Romero-Buján MI (1994) Omphalodo nitidae-Coryletum avellanae, a new mesophytic woodland community of the northwest Iberian Peninsula. Botanica Helvetica 104: 103–122.

Bardat J, Bioret F, Botineau M, Boullet V, Delpech R, Géhu J-M, Haury J, Lacoste A, Rameau J-C, Touffet J (2004) Prodrome des végétations de France.Museum National d’Histoire naturelle,Paris, FR,171 pp.

Boeuf R, Simler N, Holveck P, Hum P, Cartier D, Ritz F (2014) Les végétations forestières d’Alsace. Vol. I (Textes).Scheuer,Drulingen, FR,371 pp.

Braun-Blanquet J (1933) Prodrome des groupements végétaux – Prodromus der Pflanzengesellschaften. Fasc. 1 (Ammophiletalia et Salicornietalia médit.).Comité International du Prodrome Phytosociologique,Montpellier, FR,23 pp.

Braun-Blanquet J (1936) Un joyau floristique et phytosociologique. «L’ Isoetion » méditerranéen. Bulletin de la Société d’Etude des Sciences Naturelles de Nîmes 47: 141–163.

Braun-Blanquet J (1948–1950) Übersicht der Pflanzengesellschaften Rätiens. Vegetatio 1: 29–41, 129–146, 285–316; 2: 20–37, 214–237, 341–360.

Braun-Blanquet J (1961) Die inneralpine Trockenvegetation. Von der Provence bis zur Steiermark.Gustav Fischer,Stuttgart, DE,273 pp.

Braun-Blanquet J, Diemont W (1936) Bibliographia Phytosociologica. Fasc. 3, Regio Mediterranea.Mari-Lavit,Montpellier, FR,20 pp.

Braun-Blanquet J, Moor M (1938) Prodromus der Pflanzengesellschaften. 5. Verband des Bromion erecti.Comité International du Prodrome Phytosociologique SIGMA,Montpellier, FR,64 pp.

Brullo S, Minissale P (1998) Considerazioni sintassonomiche sulla classe Isoeto-Nanojuncetea [Syntaxonomic considerations on the class Isoeto-Nanojuncetea ]. Itinera Geobotanica 11: 263–290.

Chytrý M [Ed.] (2007) Vegetace České republiky. 1. Travinná a keříčková vegetace [Vegetation of the Czech Republic. 1. Grassland and heathland vegetation].Academia,Praha, CZ,526 pp.

Chytrý M [Ed.] (2013) Vegetace České republiky 4. Lesní a křovinná vegetace [Vegetation of the Czech Republic 4. Forest and scrub vegetation].Academia,Praha, CZ,551 pp.

Costa JC, Neto C, Aguiar C, Capelo J, Espírito Santo MD, Honrado J, Pinto-Gomes C, Monteiro-Henriques T, Sequeira M, Lousã M (2012) Vascular plant communities in Portugal (Continental, the Azores and Madeira). Global Geobotany 2: 1–180.

Delarze R, Gonseth Y, Eggenberg S, Vust M (2015) Guide des milieux naturels de Suisse: écologie – menaces – espèces caractéristiques. Bussigny, Rossolis, CH.

De Leeuw WC (1935) Bibliographia Phytosociologica. Fasc. 2, Nederlandia. Hannover, DE.

Díaz TE, Fernández Prieto JA (1994) La vegetación de Asturias. Itinera Geobotanica 8: 243–528.

Fernández-González F, Silva V, Theurillat J-P (2021) Proposals (26–27) : to conserve the names Nanocyperetalia Klika 1935 and Isoetetalia Braun-Blanquet 1936. Vegetation Classification and Survey 2: 65–69. https://doi.org/10.3897/VCS/2021/66398

Issler E (1924) Les associations végétales des Vosges méridionales et de la Plaine Rhénane avoisinante. Première Partie. Les forêts. A. Les associations d’arbres feuillus. Documents sociologiques. Bulletin de la Société d’Histoire Naturelle de Colmar N. S. 17: 1–65.

Issler E (1926) Les associations végétales des Vosges méridionales et de la Plaine Rhénane avoisinante. Première Partie. Les forêts (fin). Documents sociologiques. Bulletin de la Société d’Histoire Naturelle de Colmar N. S. 19: 1–109.

Klika J (1928) Geobotanická studie rostlinných společenstev Velké Hory u Karlštejna [Geobotanical study of plant communities of the Velká hora near Karlštejn]. Rozpravy České Akademie Věd, třída 2, vědy mathematické, přírodní 37/12: 1–42.

Klika J (1931) Studien über die xerotherme Vegetation Mitteleuropas. I. Die Pollauer Berge im südlichen Mähren. Beihefte zum Botanischen Centralblatt, Abt. 2, 47: 343–398.

Koch W (1926) Die Vegetationseinheiten der Linthebene unter Berücksichtigung der Verhältnisse in der Nordostschweiz. Jahrbuch der St. Gallischen Naturwissenschaftlichen Gesellschaft 61: 1–146.

Korneck D (1974) Xerothermvegetation von Rheinland-Pfalz und Nachbargebieten. Schriftenreihe für Vegetationskunde 7: 5–196.

Leuschner C, Ellenberg H (2017) Ecology of Central European forests. Vegetation ecology of Central Europe, Volume I.Springer,Cham, CH,971 pp. https://doi.org/10.1007/978-3-319-43042-3

Loidi J, Amigo J, Bueno Á, Herrera M, Rodríguez-Guitián MA (2022) Proposal (30) to conserve the name Polysticho setiferi-Fraxinetum excelsioris (Tüxen et Oberdorfer 1958) Rivas-Martínez ex Díaz et Fernández Prieto 1994 with a conserved type. Vegetation Classification and Survey 3: 187–189. https://doi.org/10.3897/VCS.86799

Moor M (1973) Das Corydalido-Aceretum, ein Beitrag zur Systematik der Ahornwälder. Berichte der Schweizerischen Botanischen Gesellschaft 83: 106–132.

Moor M (1976) Gedanken zur Systematik mitteleuropäischer Laubwälder. Schweizerische Zeitschrift für Forstwesen 127: 327–340.

Moravec J (1998) Přehled vegetace České republiky, Svazek 1, Acidofiné doubravy [Acidophilous oak forests].Academia,Praha,64 pp. [in Czech]

Mucina L, Grabherr G, Ellmauer T [Eds] (1993) Die Pflanzengesellschaften Österreichs. I. Anthropogene Vegetation.Gustav Fischer,Stuttgart, DE,578 pp.

Mucina L, Bültmann H, Dierßen K, Theurillat J-P, Raus T, Čarni A, Šumeroba K, Willner W, Dengler J, Tichý L (2016) Vegetation of Europe: hierarchical floristic classification system of vascular plant, bryophyte, lichen, and algal communities. Applied Vegetation Science 19 (Suppl. 1) : 3–264. https://doi.org/10.1111/avsc.12257

Novák P (2019) Proposals (23–25) : to conserve the names Galio-Carpinetum Oberdorfer 1957, Lithospermo-Carpinetum Oberdorfer 1957, and Stellario-Carpinetum Oberdorfer 1957. Phytocoenologia 49: 409–411. https://doi.org/10.1127/phyto/2019/0346

Novák P, Willner W, Zukal D, Kollár J, Roleček J, Świerkosz K, Ewald J, Wohlgemuth T, Csiky J, Chytrý M (2020) Oak-hornbeam forests in central Europe: a formalized classification and syntaxonomic revision. Preslia 92: 1–34. https://doi.org/10.23855/preslia.2020.001

Oberdorfer E (1957) Süddeutsche Pflanzengesellschaften.Gustav Fischer,Jena, DE,564 pp.

Oberdorfer E [Ed.] (1992) Süddeutsche Pflanzengesellschaften, 2. Auflage, Teil IV, Wälder und Gebüsche.Gustav Fischer,Jena, DE,282 pp.

Pallas J (1996) Beitrag zur Syntaxonomie und Nomenklatur der bodensauren Eichenmischwälder in Mitteleuropa. Phytocoenologia 26: 1–79. https://doi.org/10.1127/phyto/26/1996/1

Preising E, Weber HE, Vahle H-C (2003) Die Pflanzengesellschaften Niedersachsens – Bestandsentwicklung, Gefährdung und Schutzprobleme. Wälder und Gebüsche. Naturschutz und Landespflege in Niedersachsen 20/2: 1–139.

Rivas Goday S (1970) Revisión de las comunidades hispanas de la clase Isoeto-Nanojuncetea Br.-Bl. & Tüxen 1943. Anales del Instituto Botánico A. J. Cavanilles 27: 225–276.

Rivas-Martínez S, Fernández-González F, Loidi J, Lousâ M, Penas A (2001) Syntaxonomical checklist of vascular plant communities of Spain and Portugal to association level. Itinera Geobotanica 14: 5–341.

Rodríguez-Guitián MA, Amigo Vázquez J (2022) Proposal (29) to conserve the name Omphalodo nitidae-Coryletum avellanae Amigo, G. Azcárate et Romero 1994 with a conserved type. Vegetation Classification and Survey 3: 145–148. https://doi.org/10.3897/VCS.76387

Roleček J (2013) Acidofilní doubravy (Quercetea robori-petraeae) [Acidophilous oak forests]. In: Chytrý M [Ed.] Vegetace České republiky. 4. Lesní a křovinná vegetace. Academia, Praha, 347–365. [in Czech]

Scherrer M (1925) Vegetationsstudien im Limmattal. Veröffentlichungen des Geobotanischen Institutes Rübel in Zürich 2: 1–115.

Silva V, Molina JA (2021) Requests (1–2) for a binding decision on the name-giving taxa in the names Isoeto-Cicendietum Br.-Bl. 1967 and Verbeno-Gnaphalietum Rivas Goday 1970. Vegetation Classification and Survey 2: 71–72. https://doi.org/10.3897/VCS/2021/68430

Slezák M, Kliment J, Valachovič M (2021) Request (4) and Proposal (28) : to conserve the name Molinio arundinaceae-Quercetum roboris Neuhäusl et Neuhäuslová-Novotná 1967. Vegetation Classification and Survey 2: 237–239. https://doi.org/10.3897/VCS/2021/71490

Soó R (1931) Adatok a Balatonvidék vegetációjának ismeretéhez III [Contributions to the knowledge of the vegetation of the Balaton area III]. A Magyar Biologiai Kutató Intézet Munkái 4: 293–319.

Soó R (1940) Vergangenheit und Gegenwart der pannonischen Flora und Vegetation. Nova Acta Leopoldina 56: 3–49.

Terzi M, Di Pietro R, Theurillat J-P (2016) Nomenclature of the class Festuco-Brometea in Italy and remarks on the interpretation of articles 1 and 2b ICPN. Botany Letters 163: 307–319. https://doi.org/10.1080/23818107.2016.1201692

Terzi M, Di Pietro R, Theurillat J-P (2021) Request (3) for a binding decision on the valid publication of the names Xerobromion and Mesobromion in Zoller 1954. Vegetation Classification and Survey 2: 233–235. https://doi.org/10.3897/VCS/2021/74046

Theurillat J-P, Terzi M, Di Pietro R (2017) Proposal (22) : to conserve the name Mesobromion erecti (Br.-Bl. & Moor 1938) Oberd. 1957 against the name Bromion erecti W. Koch 1926. Phytocoenologia 47: 385–387. https://doi.org/10.1127/phyto/2017/0187

Theurillat J-P, Willner W, Fernández-González F, Bültmann H, Čarni A, Gigante D, Mucina L, Weber H (2021) International Code of Phytosociological Nomenclature. 4th edition. Applied Vegetation Science 24: e12491. https://doi.org/10.1111/avsc.12491

Tüxen R (1928) Bericht über die pflanzensoziologische Exkursion der floristisch-soziologischen Arbeitsgemeinschaft nach dem Pleßwalde bei Göttingen am 14. August 1927. Mitteilungen der Floristisch-Soziologischen Arbeitsgemeinschaft in Niedersachsen 1: 25–51.

Tüxen R (1930) Ueber einige nordwestdeutsche Waldassoziationen von regionaler Verbreitung. Jahrbuch der Geographischen Gesellschaft zu Hannover für das Jahr 1929: 55–116.

Tüxen R, Prügel E (1935) Bibliographia Phytosociologica. Fasc. 1, Germania. Hannover, DE.

Tüxen R, Oberdorfer E (1958) Die Pflanzenwelt Spaniens. II Teil. Veröffentlichungen des Geobotanischen Institutes Rübel in Zürich 32: 1–328.

Valachovič M, Kliment J, Hegedüšová Vantarová K (2021) Rastlinné spoločenstvá Slovenska. 6. Vegetácia lesov a krovín [Plant communities of Slovakia. 6. Forest and shrub vegetation].VEDA,Slovenská akadémia vied, Bratislava, SK,766 pp.

Weeda EJ, Schaminée JHJ, van Duuren L (2002) Atlas van Plantengemeenschappen in Nederland. 2. Graslanden, zomen en droge heiden.Utrecht,KNNV Uitgeverij, NL,224 pp.

Willner W, Grabherr G (2007) Die Wälder und Gebüsche Österreichs. Ein Bestimmungswerk mit Tabellen.Spektrum Akademischer Verlag,Heidelberg, DE,302 pp.

Willner W, Roleček J, Korolyuk A, Dengler J, Chytrý M, Janišová M, Lengyel A, Aćić S, Becker T, Yamalov S (2019) Formalized classification of semi-dry grasslands in central and eastern Europe. Preslia 91: 25–49. https://doi.org/10.23855/preslia.2019.025

Willner W, Čarni A, Fernández-González F, Pallas J, Theurillat J-P (2021) Report 2 of the Committee for Change and Conservation of Names (CCCN). Vegetation Classification and Survey 2: 305–309. https://doi.org/10.3897/VCS/2021/78172

Zoller H (1954) Die Typen der Bromus erectus -Wiesen des Schweizer Juras – ihre Abhängigkeit von den Standortbedingungen und wirtschaftlichen Einflüssen und ihre Beziehungen zur ursprünglichen Vegetation. Beiträge zur Geobotanischen Landesaufnahme der Schweiz 33: 1–309.