New combinations in Crystallopollen Steetz (Asteraceae: Vernonieae), the correct name for the illegitimate Polydora Fenzl ex H.Rob.

here for C. bainesii (Oliv. & Hiern) serratuloides sylvicola J.C.Manning.


Introduction
The genus Polydora Fenzl (1844) (Asteraceae: Vernonieae) is one of twelve segregates of Vernonia Schreb. that were recognised by Robinson et al. (2016) in their synopsis of the southern African members of the tribe Vernonieae. It comprises mostly annual herbs with L-shaped or asymmetrically T-shaped hairs on the stems, a 6-or 7-seriate involucre of acute to awned bracts and lophate, pantoporate pollen (Robinson et al. 2016;Swelankomo et al. 2018). The generic circumscriptions adopted by Robinson et al. (2016) followed his earlier conclusion (Robinson 1999) that Vernonia in the narrow sense was restricted to the Western Hemisphere, and that the African and Asian taxa previously included in it had to be removed to other genera in order to render it monophyletic.
The revised classification proposed by Robinson (1999) was adopted for the southern African flora by Herman and Swelankomo (2011), who provided a nomenclator for the flora of the region. This was superseded by the more comprehensive synopsis provided by Robinson et al. (2016). None of these three accounts included critical taxonomic assessments of the species themselves. These have now been provided for some of the genera, viz. Distephanus Cass. (Swelankomo & Manning 2014), Gymnanthemum Cass. (Swelankomo et al. 2016a), Hilliardiella H.Rob. (Swelankomo et al. 2016b) and most recently Polydora Fenzl (Swelankomo et al. 2018).
It has since emerged that the generic name Polydora was not validly published by Fenzl (1844) and that the earliest available name for the genus is Crystallopollen Steetz ([in Peters] 1864). We examine this issue here and summarise the New combinations in Crystallopollen Steetz (Asteraceae: Vernonieae), the correct name for the illegitimate Polydora Fenzl ex H.Rob. nomenclature, as well as providing several new combinations in Crystallopollen for taxa currently recognised in Polydora.

Materials and methods
Nomenclatural decisions follow the latest version of the International Code of Nomenclature for algae, fungi, and plants (Shenzhen Code) (Turland et al. 2018). The list of species accepted in Polydora follows that provided by Robinson (1999) and Swelankomo et al. (2018) with additions from Pope (1992).

Results and nomenclature
The generic name Polydora was published by Fenzl (1844) in a checklist as the simple binomial P. stoechadifolia, and was thus not validly published here, as it lacked an accompanying description or reference to such a description (Turland et al. 2018: ICN, Art. 38.1). The binomial P. stoechadifolia Fenzl (1844) is likewise a nomen nudum. This name is currently regarded as a synonym of P. serratuloides (DC.) H.Rob. (1999). Robinson (1999) overlooked the fact that Polydora was not validly published, and his description of the genus constitutes its valid publication, and it is thus to be attributed to him. In a further complication, his inclusion of the earlier validly published Crystallopollen Steetz ([in Peters] 1864) as a synonym, which should have been adopted as the earliest available name, renders Polydora Fenzl ex Robinson (1999) an illegitimate superfluous name (Turland et al. 2018: ICN, Art. 52.1).
Crystallopollen Steetz ([in Peters] 1864) was published for the two species C. angustifolium Steetz and C. latifolium Steetz, without the designation of a type. The citation by Robinson (1999) of C. angustifolium as the type of Crystallopollen is thus to be regarded as designation of that species as the type (Turland et al. 2018: ICN Art. 10.2). The combination of this name in Polydora was also provided by Robinson (1999). The second species, C. latifolium, is the type of Vernoniastrum H.Rob. (1999).
The generic name Crystallopollen Steetz is thus the earliest available name for the group of species treated as Polydora by Robinson (1999) and later authors. Unfortunately, only one of the several species that are currently included in the genus has a combination in Crystallopollen and we therefore provide the necessary combinations here. Typification of the names is provided in Pope (1986) and Swelankomo et al. (2018).