from 1912 until 2011 , the various editions of the rules and codes that regulated the names of fungi , provided for the separate naming of asexual and sexual morphs of the same species . the detailed requirements varied markedly under different sets of provisions , especially before and after the decisions of the 1981 sydney congress . while the mycologists present at the melbourne congress in 2011 worked to provide rules that would minimize the disruption of well - established and familiar names , now included in the international code of nomenclature for algae , fungi , and plants ( icn ; mcneill et al . here we draw attention to one of those situations , and propose a possible solution . some of the previous sets of rules governing the names of different morphs of a single fungus species , include one that stated that species names typified by an asexual morph could not be combined legitimately into a genus , the name of which was typified by a sexual morph . however , under later versions of the rules , such a combination would be legitimate but only apply to the morph of the basionym , regardless of the generic name used . for many years , where new combinations were made under a generic name with a sexually typified type , they were ruled instead as names of new species provided that the other requirements of valid publication were met . this was so even though the author had clearly indicated that a new combination was being made and not a new species described . that situation can be illustrated by a case given in various editions of the codes . mycosphaerella aleuritidis ( miyake ) s. h. ou 1940 , published as a new combination on discovery that the fungus had a sexual morph belonging to mycosphaerella , but with the asexually typified cercospora aleuritidis miyake 1912 as basionym , was nevertheless treated as a new species mycosphaerella aleuritidis s. h. ou 1940 , attributed to ou alone , as a latin description of the sexual morph had been included ( e.g. vienna code art . 59 ex . 6 ; mcneill et al . 2006 ) . with the changes effected at the melbourne congress in 2011 , enabling names to compete regardless of the morph represented by their name - bearing types , ou s combination can be accepted as legitimate and the original citation has to be reinstated as mycosphaerella aleuritidis ( miyake ) s. h. ou 1940 ( melbourne code art . some mycologists , especially ones working with plant and human pathogens , were conscious of the importance of minimizing the disruption of names when sexual morphs were discovered and sought to retain a thread of familiarity . they achieved this by using the same species epithet in the sexually typified generic name , but with a sexual morph designated as type of that name . indeed , this was commended as good - practice by many mycologists , and became the norm in the case of plant pathogens . examples are : the coffee pathogen gibberella stilboides w. l. gordon & c. booth 1971 , introduced for the sexual morph of the asexually typified fusarium stilboides wollenw . 1924 ( vienna code art . 2009 introduced on discovery of a sexual morph in the asexually typified aspergillus fumigatus fresen . 1863 , the primary agent of sometimes fatal human aspergillosis . in these and similar cases , the sexual morph names are accompanied by a latin description or diagnosis and designation of a name - bearing type in which the sexual stage is present . under the melbourne 
 code ( mcneill et al . 2012 ) , names typified by a sexual or an asexual morph compete on an equal footing for priority . as names such as gibberella stilboides and neosartorya fumigata have different types than fusarium stilboides and aspergillus fumigatus respectively , they are nomenclaturally independent and have priority only from 1971 not 1924 , and 2009 not 1863 , respectively . this means that it would not be possible to recombine the earliest epithet in the same rank into a genus considered appropriate on taxonomic grounds as it would be pre - occupied . a problem arises in these two examples if there is an asexual morph - typified and legitimate name with a different epithet , which is a synonym published before 1971 and 2009 , respectively . under the melbourne code , such a name would be priorable and have to be combined into the desired genus . this is irrespective of how unfamiliar that name might be and , unless it is formerly proposed for rejection or included in one of the proposed lists of protected fungal names , it would have to be taken up . ( 1 ) an instance where two identical epithets are involved , but where a type was not explicitly designated for the sexual morph , is provided by ceratocystis paradoxa ( dade ) c. moreau 1952 , a species which causes stem and other rots in banana , cocoa , coconut , oil palm , pineapple , sugarcane and other mainly tropical plants . moreau s combination was based on ceratostomella paradoxa dade 1928 , a name introduced on discovery of the sexual morph of sporoschisma paradoxum de seynes 1886 ( syn . 1892 ; thielaviopsis paradoxa ( de seynes ) hhn . 1904 ) in artificial culture . de seynes s name was listed as a synonym ( i.e. as the asexual morph ) , a latin description was provided , and dade did not include  de seynes  in his ascription . it is also clear that he was only introducing a new taxon name without  de seynes  as that was required by the rules in force at the time ( brussels rules , 
 briquet 1912 ) . dade used a single isolate for his experiments , but he did not use the word  type  . but under the current rules , in which names of pleomorphic fungi must in general conform to the same provisions as other names , dade should indeed have published a new combination based on sporoschisma paradoxum de seynes . however , because dade used  the epithet that ought to have been adopted 52.1 ) , he did not create a superfluous name ; consequently , as no other provisions of the melbourne code apply , his supposed new species name can be treated as a new combination . this would apply regardless of the organism involved , for example whether a plant or fungus a problem would arise , however , had dade designated a different type , because under art . 9.1 and note 1 , the author s designation of a type  is final  , the name can not simply be treated as a new combination homotypic with de seynes s name . moreover , if de seynes s and dade s names are treated as nomenclaturally separate with different types , although the earliest name for the species under the icn is that of de seynes , it could not be combined into ceratocystis as the binominal is pre - occupied by moreau s heterotypic name . paradoxa  in ceratocystis would date from 1928 and not from 1886 . as there is a pre-1928 synonym available , stilbochalara dimorpha ferd . & winge 1910 , that would mean that the correct name for this fungus would be a new combination based on s. dimorpha , unless that name was proposed formally for rejection or suppresion . ( 2 ) a case in which a species has two identical epithets , one with a sexual morph type and one with an asexual morph type , and the new rules would mean that a different unfamiliar name would have to be used , is that of venturia carpophila e. e. fisher 1966 . that fungus is responsible for freckle or scab diseases in almonds , apricots , peaches , and plums . fisher discovered the sexual morph on overwintering leaves , and designated a type with the sexual morph , while listing cladosporium carpophilum thm . 1877 , typified by the asexual morph , as if a synonym . in this instance , thmen s name , although the earliest for the fungus , can not be combined into venturia because it is preoccupied there by that of fisher . a consequence of this situation is that the earliest available epithet at species rank for this plant pathogen in venturia becomes the almost unused fusicladium pruni ducomet 1907 . ducomet s name would have to be combined into venturia by a strict application of the melbourne code as it has priority of 59 years over fisher s name , unless ducomet s name was proposed for rejection or suppression . in principle it would be possible to deal with such cases under the melbourne code , either through the conservation / rejection or protected / suppressed lists . however , formal proposals for conservation and rejection under the icn are time - consuming to prepare , involve voting by the nomenclature committee for fungi ( ncf ) , and often take more than a year to a recommendation . the adoption of lists of protected and suppressed names will similarly be a protracted one , to judge from experience to date . against this background , mycologists working in diverse applied aspects of the subject are becoming impatient to desperate to know now what names should be used in their current publications , and in plant quarantine , health and safety , and other legal documents . we consider that an alternative approach that could be applied automatically and immediately is required , and would not require any committee action or the publication of separate proposals . in cases where a different morph is being described , the authors recognize that they are not describing a new species , only a morph of an already known species , even where different types were designated . we suggest that the principles adopted in the mycosphaerella aleuritidis case in previous codes , noted above , are extrapolated to ones where a name was introduced as a new species using the same epithet as that of a previously named different morph listed as a synonym . that is , that names such as dade s and fisher s which were originally cited with them as the sole authors , have to be treated as errors to be corrected to that of new combinations and not independently typified new species names . implementation of this proposal in the principle nomenclatural databases , mycobank and species fungorum , will necessarily be a piecemeal process given the limited resources available , and it would be helpful if mycologists encountering such cases altered the curators so that they could implement the changes . the principle argument in support of this interpretation is that such names were introduced not because the author considered that a new species had been found , but because this was a requirement of the code then in force . however , unless limited by date , it is a regular practice for rules adopted by one congress to be retroactive . indeed , in the case of mycology , this has been the situation with regard to issues such as the starting point dates for nomenclature , the acceptance of metabolically inactive cultures as name - bearing types , and the different versions of art . we consider , therefore , that an author s use of the same epithet is evidence which , had the possibility to make a combination been permitted by the rules in force at the time , a combination would have been made . indeed , it must be viewed as ironic that the consequence of an author using the same epithet for a newly found sexual morph with the intention of avoiding a change in epithet of a species previously known only as an sexual morph , can lead to that epithet no longer being available under the melbourne code . the proposal made here must , therefore , be seen as in line with the intent of the author of the later name . in particular , it is also in accord with the thrust of the code as expressed in art . 41.4 , in which  if no reference to a basionym is given but the conditions for its valid publication as the name of a new taxon or replacement name are fulfilled , that name is nevertheless treated as a new combination or name at new rank when this was the author s presumed intent and a potential basionym applying to the same taxon exists . formal proposals for changes to the melbourne icn are not being accepted for publication in taxon until 2014 , and even if then supported by the nomenclature committee for fungi ( ncf ) and the general committee on nomenclature , any rule change would not be ratified until the 2017 shenzhen congress . we consider that interim action is necessary to avoid the disruption of familiar epithets in such instances . consequently , in anticipation of approval of an eventual change in the icn at the congress in 2017 , we suggest that mycologists now confronted with this situation adopt the following working practice : if , prior to 1 january 2013 , an author in introducing a new species name for the sexual morph of a fungus which had an earlier name typified by an asexual morph , adopted the same species epithet as that of the previously described asexual morph , the author s name is to be treated as a new combination and not that of a new species with a separate type . designations such as  sp . nov .  and ascriptions excluding the earlier asexually - typified name are to be treated as formal errors requiring correction . we further propose that this same practice be adopted in the converse situation , i.e. where the name typified by a sexual morph was the first published and the same epithet was used for the subsequently named asexual morph . in cases where an author designated a holotype , lectotype , or neotype , as the name is being treated as a new combination under the working practice proposed here , that designation would have no nomenclatural standing . 7.3 ) . in some cases it may be convenient to designate the type indicated by the author introducing the new name , or that of a later author in the case of a lecto- or neo - typification , as an epitype to show the sexual morph of the basionym however , in perhaps a majority of cases , it would be more helpful to designate a modern culture or specimen , especially one that has been sequenced and also has the sexual morph , as an epitype for the type of the basionym . each case will have to be examined individually with respect to the issue of epitypification . this proposal would go some way to addressing the legitimate concern of gams et al . ( 2012a ) that established and much - used combinations under the generic name now of choice may be liable to disruption , because of priorable names hitherto treated as being restricted to asexual morphs of the same species . we regret that this particular case was not covered in the changes made with respect to the naming of pleomorphic fungi at the melbourne congress in 2011 , and that a final decision will now have to await the 2017 shenzhen congress .
the abolition of the separate naming of different morphs of the same fungal species in 2011 will inevitably result in many name changes in some genera . 
 the working practices commended here are intended to minimize one category of these changes , that which can arise as a consequence of an author using the epithet of an asexual morph when describing the sexual morph of the same species . 
 we consider that name proposed for the sexual morph in such cases should be treated as a formal error for a new combination and not as a new species , and so be corrected . 
 this is interpreted as applying even where the author indicated that a new species was being described and designated a type . 
 we argue that those formalities were a result of the requirements of the rules then in force , as the author recognized that a morph of a named species was being described , and not a new hitherto unnamed species was being reported  but was barred from making a new combination so used the same epithet for the new morph name instead . where a type with the sexual morph was designated for the sexual morph , under this interpretation that no longer has nomenclatural status , the type being that of the basionym . 
 the material for the sexual morph indicated as a type , would be available for designation as an epitype , though a modern sequenced sample with both sexual and asexual morphs would be more informative as an epitype in many cases . a proposal to regularize the working practice commended here , and also the converse situation where the sexual morph typified name is the earlier , will be made to the 2017 shenzhen congress .