Lectotypification of five subspecies names of Hieracium auriculoides and H. brachiatum (Asteraceae) described from the North Caucasus by D.I. Litvinov and K.H. Zahn

Five names of subspecies of Hieracium s.l. (Asteraceae) described from the North Caucasus by D.I. Litvinov and K.H. Zahn are lectotypified: Hieracium auriculoides Láng subsp. basileucum Litv. et Zahn, H. auriculoides subsp. sabiniceps Litv. et Zahn (≡ H. auriculoides subsp. sabinocephalum Litv. et Zahn, nom. illeg.), H. auriculoides subsp. sublasiophorum Litv. et Zahn, H. auriculoides subsp. umbelliforme Litv. et Zahn (≡ H. auriculoides subsp. subumbelliforme Zahn, nom. illeg.; H. subumbelliforme Üksip), and H. brachiatum Bertero ex DC. subsp. alticaule Litv. et Zahn. For each subspecies, the following data are provided: basionym, main synonyms, information about type localities according to the protologue, lectotype (isolectotypes, syntypes, if applicable) and their herbarium barcodes, and nomenclatural notes. In addition, scanned images of all newly designated lectotypes are presented.


Introduction
Hieracium s. l. (including currently recognized segregate genera Hieracium L. and Pilosella Vaill., Asteraceae) is considered among the most taxonomically and nomenclaturally difficult groups of genera because of the processes of intensive interspecific hybridization and apomixis observed in some species groups. According to various estimates, the number of taxonomic units described in this group is more than 15 000 (IPNI, http://www.ipni.org/index.html), with about 6 000 taxa being considered apomicts (Shaw, Willis, 1985). Therefore, there are some problems with identification of plants of Hieracium and Pilosella because their specific morphological characteristics are often not clearly manifested, or the same or similar characters are sometimes present in representatives of several geographically distant and taxonomically distinct groups. Because of that, for addressing various issues of taxonomy of Hieracium s. l., comprehensive studies are conducted using anatomical, morphological, populational, genetic, and recently also molecular phylogenetic methods (Sennikov, Illarionova, 2002;Suda, 2007;Zini, 2008;Qurwshi, 2009, etc.).
Because of the large number of infrageneric and infraspecific entities described within Hieracium s. l., there is some confusion in delimiting and understanding their taxonomic borders. Therefore, important steps toward resolving taxonomic and nomenclatural problems in this group include proper typification of names applied to various taxa. There are not so many articles about typification of names in Hieracium s. l. as could be expected (Gubanov, 2002;Sennikov, 2007;Szeląg, 2007Szeląg, , 2011Tyler, 2007, etc.). Consequently, search for original material and typification of names in Hieracium s. l. not only provides a clearer picture of particular species, subspecies, varieties, etc., but also serves for better resolution of taxonomy of the group and floristic research. It is also an important basis for solving the problem of understanding the concepts of "species" (agamospecies, microspecies etc.) and "species aggregates" within the group (Manton, 1958;Üksip, 1960;Sennikov, 2003 etc.).
When managing and inventorying the collections of Hieracium s. l. in the National Herbarium of Ukraine (KW -Herbarium of the M.G. Kholodny Institute of Botany of the NAS of Ukraine), we studied specimens of exsiccates Herbarium Florae Rossicae (HFR) where some taxa of this genus were published. It has become evident that several names of subspecies in Hieracium s. l., those described by the German botanist K.H. Zahn Note. Zahn (1907) provided no information about the collection date in the protologue of H. auriculoides subsp. basileucum. However, another (later) description of the subspecies was published in 1911 in the HFR exsiccata, in volume 7 of that series edited by Litvinov (Litwinow, 1911 (Litwinow, 1911). Because of that, for each specimen of No. 2051, one of these two dates was underlined manually on the label, indicating the collection date of that particular specimen (see Fig. 1). More than half of original specimens of H. auriculoides subsp. basileucum that we studied were collected on 28.VI 1905.
We designate here the specimen LE 01024063 ( Fig. 1) as the lectotype of H. auriculoides subsp. basileucum; it was collected by Litvinov on 28.VI 1905. This specimen has a typographically printed HFR label with the taxon name, a detailed Latin description by Zahn, the location and date of collection. The remaining original specimens from LE collected by Litvinov on 28.VI 1905 are not published exsiccates; they have handwritten labels. Identification of plants (as "Hieracium panonicum N.P. subsp. basileuciim Litw. et Zahn") and the actual text in these labels has some differences in ink color, indicating some time lag between the collection of this material and its processing.

Hieracium auriculoides Láng subsp. sabiniceps
Litv. et Zahn, 1907, Repert. Spec. Nov. Regni Veg. 4: 190, "sabinocephalum in litt.";Zahn, 1923, in   The names of taxa are listed alphabetically; for each taxon, the following data are provided: basionym; a short nomenclatural note that include only main synonyms; information about the type (or syntypes) according to protologue; lectotype (isolectotypes, syntypes, as applicable) and their herbarium barcodes (if available); and nomenclatural comments (if necessary). If information about a specimen was taken from online resources, the barcode and web address (URL) are provided.
Note. It is likely that the authors used in their correspondence two alternative names before validating this subspecies. When describing new taxa in 1907, Zahn used the name H. auriculoides Láng subsp. sabiniceps Litv. et Zahn, but also noted that this subspecies was named (in his letter) as "sabinocephalum" (Zahn, 1907). The latter epithet was used for original material published in HFR under No. 2057 (Litwinow, 1911), but the protologue erroneously reported other values of the altitude above sea level than those indicated on Litvinov's specimens. Therefore, to correct errors in citing the type, in 1923 Zahn reported that taxon as "Subsp. 20. Quellen der Teberda, 2270 m, in der Provinz Kuban!" (Zahn, 1923). We designate here as the lectotype of H. auriculoides subsp. sabiniceps one of duplicates collected by Litvinov (LE 01026015) and published in HRF (as "sabinocephalum") under No. 2057.
Note. A duplicate description of H. auriculoides Láng subsp. sublasiophorum Litv. et Zahn was provided in HFR under No. 2058(Litwinow, 1911 (Litwinow, 1911). Texts of the description in "Schedae..." (Litwinow, 1911) and on labels of specimens (Fig. 5) are identical with the text in the protologue (Zhahn, 1907). We designate here as the lectotype one of duplicates collected by Litvinov (LE 01026014) and published in HRF under No. 2064а, which is now deposited in LE; the corresponding locality was mentioned in the protologue (Zahn, 1923). It should be noted that Litvinov published under No. 2064b also specimens of the same taxon from another locality.
Considering the studied original materials of H. auriculoides subsp. umbelliforme, we designate here as the lectotype one of duplicates collected by Litvinov (LE 01026020), the one which was published in HRF under No. 2061b.