Nomenclatural notes on Cruciferae заметки о крестоцветных (Cruciferae)

A generic name Dvorakia and combinations Arabidopsis amurensis, A. media, A. multijuga, A. septentrionalis, Dvorakia alaica, D. alyssifolia, Erophila acutidentata, E. aquisgranensis, E. kohlscheidensis, and E. strigosula are validated. Places of valid publication and (except for the first combination) authorship for Erysimum krynitzkii, Eunomia bourgaei, E. rubescens, Pseudocamelina aphragmodes, P. campylopoda, and Thlaspi hastulatum are corrected. For Pseudocamelina and Peltariopsis, information on the types is clarified. Some further minor nomenclatural items are commented.

There is no consensus among authors regarding the status of the considered plant which is treated either as a subspecies of Arabidopsis arenosa (L.) Lawalrée (e. g., Al-Shehbaz, O'Kane, 2002;Marhold, 2011;Danihelka et al., 2012;Buttler et al., 2018) or, less commonly, as a distinct species (e. g., Iljinska in Iljinska et al., 2007;Dorofeyev, 2012a) though it is generally agreed that the above two heterotypic sets of names belong to the same entity. As follows from the above synonymy [Al-Shehbaz, O'Kane (2002) can be consulted for further names involved], under such concept the final epithet "borbasii" has priority only at the rank of subspecies while at the species level, as accepted here, "multijuga" must be adopted.

North Asian Arabidopsis lyrata grex
During last two decades, multiple and various evidences (e. g., Schmickl et al., 2008Schmickl et al., , 2010Shimizu-Inatsugi et al., 2009;Hohmann et al., 2014;Novikova et al., 2016;etc.) showing that the broad concept (O'Kane, Al-Shehbaz, 1997;Al-Shehbaz, O'Kane, 2002) of several polymorphic Arabidopsis (DC.) Heynh. species somewhat simplifies the situation became available accompanied by increasing number of recognized (chiefly reinstated) species and subspecies (Dorofeyev, 2002;Shimizu et al., 2005;Kolník, Marhold, 2006;Iljinska et al., 2007;Kadota, 2007;Elven, Murray, 2008; summarized by Koch, 2019). Nomenclaturally, the most critical situation is being observed within A. lyrata (L.) O'Kane et Al-Shehbaz complex where, due to the lack of appropriate names, the same epithet "petraea" is used at different ranks in simultaneously applied combinations, viz.  (Hohmann et al., 2014;Novikova et al., 2016), there are two options of solving this problem, also mentioned by Elven and Murray (l. c.), namely recognizing relevant entities at species or subspecies level, but then, in contrast to the latter authors' approach, under A. lyrata, as informally suggested by Koch (l. c.). In this case, however, it would need to be done not only for the morphologically poorly separable North Asian entities, but also for the most readily distinguishable A. arenicola (Richardson) Al-Shehbaz, Elven, D. F. Murray et Warwick, totally accepted as "good" species, reproductively isolated from of A. lyrata s. str. (Hohmann et al., l. c; Koch, l. c.) but genetically closest to it. Because of this and having in mind relevant commens by Elven and Murray (l. c.) as well as the viewpoint of Yurtsev et al. (2010), an alternative approach is applied here. Although other taxonomic decisions are well predictable in A. lyrata complex, the presented nomenclatural novations enable use of names in agreement with ICN when splitting concept is adopted.
Arabidopsis amurensis (N. Busch), comb. nov. ≡ Arabis amurensis N. Busch, 1922, Notul. Syst. Herb. Hort. Bot. Petrop. 3, 3-4: 12. ≡ Cardaminopsis amurensis (N. Busch) O. E. Schulz, 1936 Unlike the other two taxa below, A. amurensis was not subjected to molecular studies yet. It is given the same rank since its morphological distinction from the other two similarly recognized entities is comparable to that among them. Yet untypified Arabis ambigua DC., the oldest name potentially applicable to this species, is not listed here because it also includes elements (p. max. p.) of what is currently known as Arabidopsis kamchatica (Fisch. ex DC.) K. Shimizu et Kudoh (Busch, 1922, 1926, as Arabis kamchatica (Fisch. ex DC.) Ledeb.; Tolmaczev, 1975, as Arabis lyrata subsp. kamchatica (Fisch. ex DC.) Hult.; Shimizu et al., 2005) over which it has priority as well. Because of this heterogeneity since the treatment of Busch (1922,1926) Arabis ambigua is informally rejected Nomenclatural notes on Cruciferae and might indeed be a candidate for rejection. At the same time, being generally out of use even as a basionym (varietal level disregarding), it causes no threats at the rank of subspecies where other problems nevertheless exist. In particular, due to priority of the final epithet "media", established by Hämet-Ahti (1970), there is no appropriate name currently available in Arabidopsis for treating this taxon as a subspecies as done by Elven and Murray (l. c.) and followed by some others. The hitherto used combination Arabidopsis petraea subsp. umbrosa, otherwise invalid under ICN Art. 41.7 (Turland et al., 2018), is still validly published due to listing in synonymy, with full and direct reference, of a factual basionym, Arabis petraea subsp. umbrosa, but, again, it is anyway just a potential synonym of any subspecific combination based on A. media.
Additional question is whether Arabis media and Arabis umbrosa Turcz. ex Ledeb. are necessarily homotypic as recently treated by the typifying author (Dorofeyev, 2018: 289) which would mean illegitimacy of both Arabis petraea subsp. umbrosa and Arabidopsis petraea subsp. umbrosa under Art. 52.1 caused by the precedence of Arabis petraea subsp. media. This is apparently not so since Art. 6.13 seems to be applicable for Arabis media, providing a choice of making it either (1) a replacement name or (2) the name of a new taxon. Such choice is not obvious as Busch (1922: 14), despite claiming that "the volume of his [Turczaninow's] A. umbrosa does not correspond the delimitation of my A. media", in fact applied his binominal to the same entity, just with much more abundant material at hand than Turczaninow had, which favours the first option. However, alternative choice has been implicitly done by Dorofeyev (2017: 129) who lectotypified A. media by the specimen [and gathering] other than that by which A. umbrosa was typified (Dorofeyev, 2018). Hence, the two names are heterotypic by typification and none of the concerned subspecific combinations is illegitimate. F. Dvořák (1921Dvořák ( -2016 proposed five new generic names in Cruciferae, two of which, "Alaida" and "Promicrantha", were not validly published, both times for the reason of lacking the type indication, neither in the original works (Dvořák, 1971(Dvořák, , 1972 nor elsewhere later [commented by German (2012) and Jacquemoud (1988), respectively]. While for the prior intended genus no good morphological ground justifying its segregation from Dontostemon Andrz. ex. C. A. Mey. was found (Al-Shehbaz, Ohba, 2000) and molecular phylogeny (e. g., German et al., 2009;Friesen et al., 2016) entirely supported such a lumping approach, it does not seem to be the case for the latter one, and morphology-based conclusion of Dvořák (1972) turned to be congruent with phylogenetic data (e. g., Khosravi et al., 2009;Koch et al., 2018 [https://brassibase.cos.uni-heidelberg.de/] These four species of E. verna (L.) Chevall. aggr. were described as members of Draba L. (Bomble, 2017(Bomble, , 2018 which is in agreement with the current trend in taxonomy of this group. However, as noted previously (German, 2016), available phylogenetic data (Jordon-Thaden et al., 2010;Karl, Koch, 2013) admit both approaches, of which keeping Erophila DC. separate looks preferable to me.
Binominal Erysimum krynitzkii which is universally treated as validly published by Bordzilowski (1931) (conf. IPNI;POWO;The Plant List, 2013;etc.), was indicated in relevant work as "spec. nova [ad interim]" and thus was not validated being not definitely accepted by the author (ICN Art. 36(a), Ex. 6; Turland et al., 2018). The name was overlooked in the Flora of USSR (Busch, 1939) but was included into the Caucasian accounts by Grossheim (1949Grossheim ( : 402, 1950 and subsequently considered by Czerepanov (1973: 134). In all these and some later works, conditions of a valid publication are met, though the earliest case is evidently 9 th addition to Index Kewensis (Hill, 1938), illustrating one of the kinds of such validations highlighted by Greuter (1985: 213 The combination Eunomia bourgaei is often considered as being validated by Boissier (1867) (e. g., IPNI;The Plant List, 2013) or not treated as validly published name at all (e. g., Meyer, 2006;Tropicos. org), though none of these options is the case. Apparently, citation "Eunomia bourgaei Boiss." by Busch (1907Busch ( , 1908 who clearly accepted this and the next combination ("I assign to Eunomia the species Aethionema rubescens Boiss. and Ae. Bourgaei Boiss. that are placed by Boissier in the section Iberidella" [originally in Russian]) constitutes an indirect but unambiguous reference to the basionym [given in the prolologue as "Ae. bourgaei (Boiss. pl. Bourg. exs. sub Eunomiâ)"] meeting the requirements of Art. 41.3 (Turland et al., 2018) and resulted in a validation of relevant name. In a similar way, the combination E. rubescens was also inadvertently validated by Busch via the citation "Eunomia rubescens Schott et Ky." representing an indirect reference to the basionym ["Ae. rubescens (Schott et Ky. in Sched. sub Eunomiâ)" (Boissier, 1867)]. Noteworthy, the authorship of Aethionema rubescens is still often given as "Schott et Kotschy ex Boiss." (e. g., Meyer, 2006;Marhold, 2011;Al-Shehbaz, 2014) which is in conflict with Art. 46.3 and should be changed to "Boiss.". Another variant, "(Schott et Kotschy ex Tchih.) Boiss." (e. g., in POWO), is also inacceptable since the implied basionym, "Eunomia rubescens Schott et Kotschy ex Tchih.", is nomen nudum, as directly pointed out by Tchichatscheff (1860: 339) who listed it as a "species nondum descripta". The same is true for "Eunomia rubescens Schott et Kotschy" (see Meyer, 2006: 51). N. Busch should also be assigned here" (Busch 1928: 115, originally in Russian). Thus, Busch definitely did not include this sixth species into Pseudocamelina (Boiss.) N. Busch but only assumed such possibility, i. e., he did not accept his combination P. aphragmodes treating it as provisional and therefore leaving it invalid as determined by ICN Art. 36.1(a) (Turland et al. 2018). As the only argument agaist this conclusion, the characteristics "herbae biennes rarius perennes" in the generic description can be mentioned. Indeed, it looks like an indirect indication of inclusion of P. aphragmodes, the only perennial among species treated by Busch, into Pseudocamelina. It is clear, however, that relevant phrase comes from Boissier (1867: 247) as a part of the last sentence of his Cochlearia sect. Pseudocamelina Boiss. validating description incorporated by Busch without any alteration. Hence, it reflects the concept of Boissier, who undoubtedly included C. aphragmodes Boiss. into the section, and represents more a "rudiment" of Boissier's characteristics in Busch's work rather than the latter author's intention. One more argument proving that Busch did not accept this species as a member of Pseudocamelina is his own generic characteristics "petala alba" which is absent from Boissier's sectional description. This fits the fact that five species included by Busch into the genus in question have white flowers (rarely fading violescent) and only P. aphragmodes is clearly violet-flowered. To sum up, it is obvious that the final decision of Busch (1928) was to refrain from inclusion of C. aphragmodes to Pseudocamelina and, consequently, failure to validate relevant combination. Conditions of a valid publication were subsequently inadvertently fulfilled in several works, such as Rechinger (1968: 222), Miller (1978: 28), Esmailbegi et al. (2017: 119), Kaffash, Assadi (2017: 643). The first who did it was apparently Schulz (1936) by listing "P. aphragmodes (Boiss.) N. Busch" among representative members of Pseudocamelina thus definitely accepting the name and providing an indirect, but unequivocal reference to its basionym, Cochlearia aphragmodes Boiss. Schulz, 1936, in Engler, Pflanzenfam. 17B: 559. Nordenstam (1968 highlighted the problem of invalidity of the name "Pseudocamelina campylopoda Bornm. et Gauba" adopted by Rechinger (1968: 221 Hadač and Chrtek (1973) and since then is being universally accepted as such. However, here, like in the above case of P. aphragmodes, validation was first inadvertently reached by Schulz via the citation "P. campylopoda Bornm. et Gauba 1934" (Schulz, 1936  There are different ways of how the combination Thlaspi hastulatum is given in nomenclatural citations (e. g., Busch, 1939: 591;Hedge, 1968: 115;Meyer, 2003: 117;Dorofeyev, 2012b: 458) illustrating various interpretations concerning its authorship and validity. Zohary et al. (1980: 55) brought good piece of clarity by implicit noting that Hedge's (l. c.) citation fulfills requirements of a valid publication and were followed by Meyer (l. c.) and German (2018) in ascribing relevant transfer to Hedge. However, a more attentive checking showed that the same nomenclatural action has been done yet by Ledebour (1841).

Comments on generic types
It also seems reasonable to clarify the data on the type of above-discussed Pseudocamelina as long as respective information is confusing even though only one species, P. glaucophylla, is involved. It is listed as the generic type by Miller (1978: 26), Greuter et al. (1993: 932) and Al-Shehbaz (2012: 945, 2015; according to Rollins (1979Rollins ( : 1428 and Farr, Zijlstra (1996+), the type is not designated; finally, Esmailbegi et al. (2017: 118) reported that lectotype is chosen by Busch in Grossheim (1927: 214). Since there is no type designation in the latter work (ICN Art. 7.11, Ex. 15;Turland et al., 2018), the inadvertent choice of Miller is to be followed. Publication of relevant work shortly before issuing the ING explainably prevented taking this information into consideration by its compilers.