Eremogone (Caryophyllaceae): new combinations for Old World species

Abstract Twenty-one new combinations in Eremogone (Eremogoneae, Caryophyllaceae) are proposed to accommodate placement of all Old World taxa of Arenaria subg. Eremogone and Eremogoneastrum within Eremogone.


Introduction
In their study of relationships in Arenaria L. and major lineages within the Alsinoideae, Harbaugh et al. (2010) found that members of Arenaria subg. Eremogoneastrum F.N. Williams and Eremogone (Fenzl) Fenzl, as well as Minuartia L. subg. Spergella (Fenzl) McNeill and Th ylacospermum Fenzl, clustered in a clade that was both distantly related to the rest of Arenaria and sister to the Caryophylloideae. Th e tribe Eremogoneae was described in that paper to place this clade within the context of their tribal classifi cation of the family.
Th ree subsequent molecular studies have confi rmed the placement of the Arenaria and Minuartia species in Eremogoneae (Greenberg and Donoghue 2011;Dillenberger and Kadereit 2014;Sadeghian et al. in press). Th e fi rst two studies included a similar complement of taxa in the tribe with the exception of Th ylacospermum, which clustered with Spergula arvensis L. in those studies. While Harbaugh et al. (2010) proposed that the genus Phlebanthia Rchb. be resurrected for the species of Minuartia subg. Spergella, Dillenberger and Kadereit (2014) instead proposed new combinations in Eremogone for these taxa, noting there was not a clear segregation among the sampled taxa. We follow the results of Greenberg and Donoghue (2011) and Dillenberger and Kadereit (2014) by excluding Th ylacospermum from Eremogone at this time.
Eremogone, as now defi ned, consists of the former Arenaria subg. Eremogone (~ 70 sp.), subg. Eremogoneastrum (22 sp.), and Minuartia subg. Spergella (3 sp.). Sadeghian et al. (in press) included a larger sample of taxa now placed in Eremogone than earlier studies; they concluded that infrageneric relationships were still unclear. While many combinations in Eremogone have been published (esp., Ikonnikov (1973Ikonnikov ( , 1990) and Hartman and Rabeler (2004)), most members of Arenaria subg. Eremogoneastrum lack combinations in Eremogone. With active fl ora projects in India (Flora of India Checklist, in prep.) and China (Flora of China, e.g. Wu et al. 2001) bringing more information to light about these regions we feel that it is time to supply the 21 additional combinations to make all currently recognized taxa available in Eremogone.
Th e information about type specimens of the basionyms of the new combinations that we have included is based on examining protologues and searching major indices (Tropicos -http://www.tropicos.org/; JSTOR Global Plants -https://plants. jstor.org/) for extant specimens. Herbarium abbreviations follow Index Herbariorum (Th iers 2015). In cases where specimen deposition is not clearly stated in a protologue, we have added "?" after the abbreviation where, based on information about the location of the herbarium where the author worked and/or deposited their herbaria (see Index of Botanists -http://kiki.huh.harvard.edu/databases/botanist_index.html), we expect, but cannot confi rm, a type specimen should be deposited.
In the cases where syntypes are cited, we have refrained from designating lectotypes. It is not a requirement for the names to be validly and eff ectively published and we consider those decisions should be made during the course of a taxon-level revision where a serious study of all specimens would lead to the best selections. Description. Plants perennial, sometimes densely cespitose or pulvinate or with a stout woody caudex, very rarely annual. Leaves fi liform to subulate, often long-linear and grass-like, sometimes short and setaceous or needle-like, congested in vegetative rosettes and at or near base of fl owering stems, margin sometimes scarious, apex of-ten apiculate. Infl orescence of one or more terminal cymes, sometimes compressed to head-like, sometimes fl owers solitary or paired. Flowers weakly perigynous. Sepals often hardened at base, veins 1-3, margins often white-scarious. Petals white, rarely pink. Floral glands (nectaries) at base of the antisepalous fi laments often lobed, conspicuous. Th is combination is proposed based on the placement of this taxon in subg. Eremogone in Wu et al. (2001). Pax and Hoff mann (Pax 1922) originally thought it was close to A. przewalskii Maxim., placed in subg. Dolophragma (Fenzl) McNeill in Wu et al. (2001). Neither taxon has been included in a molecular analysis as of this writing.