Xyris pancheri Rendle, J. Bot.

Morel, Jérémie & Munzinger, Jérôme, 2021, Novitates neocaledonicae. XIII. Taxonomy and nomenclature of the genus Xyris (Xyridaceae, Poales) in New Caledonia, with description of a new species, Phytotaxa 502 (3), pp. 219-229 : 226

Xyris pancheri Rendle, J. Bot. 37: 507. 1899

Type :— NEW CALEDONIA. sin loc., sin date, Pancher 412 (holotype: BM [BM000990766] (image seen)) .

= Xyris guillauminii Conert, Senckenberg. Biol. 46(2): 185 (-188; figs.). 1965. syn. nov.

Type :— NEW CALEDONIA. Marais Kiki, plaine des lacs. 18 June 1955, H.S. MacKee 2609 (holotype: L [L1430189] (image seen), isotype: P! [P01760129]) .

Nomenclatural remarks:— Rendle (1899) pointed out that he is working on BM collections, and there was a single collection of Pancher 412 in BM ( BM 000990766). The protologue indicates “Damp hollows on dry ferruginous mountains at a height of 150 m ”, what is the exact translation of the information on the label “trous humides sur les montagnes ferrugineuses arides, alt. 150 m ” seen on BM000990766. Thus this latest is considered as the single specimen studied by Rendle, and by consequence as the holotype (see McNeill 2014). Outside the British Museum, five collections are annotated as Pancher 412, four in P [P01760143, P01760147, P01760149, P02209231] and one in S [S12-17386]. None of them bears the same information as the protologue and cannot be considered as isotypes. Finally, a specimen in K [K000457998] is signalled as type on https://plants.jstor.org, but the collection is a Pancher s.n. and cannot be considered as type.

Conert (1965: 186) designated the L specimen of MacKee 2609 as holotype of X. guillauminii , with a picture of the specimen in the publication. Surprisingly, this collection [L1430189] was not annotated by Conert, and remained with Guillaumin’s identification, made in 1955, under X. pancheri . An isotype in P was also with Guillaumin’s identification of X. pancheri . As no other specimen was identified as X. guillauminii in L or P, this name was not existing in both databases of these herbaria, while few collections were identified under that name in NOU. Furthermore, based on a previous study ( Morel et al. 2021) no morphological nor anatomical characters support the separation between X. guillauminii and X. pancheri . Therefore, we propose the synonymy of X. guillauminii under X. pancheri .

Two specimens were identified by P. Phonsena in L as X. operculata Labill. in 2010 (L.1426037 & L.1426035), while this species was never reported before in New Caledonia and was considered as endemic to Australia ( Conn and Doust 1997). The duplicates in P of these two collections were included in the analysis of Morel et al. (2021) and were identified as X. pancheri . Thus reporting the presence of X. operculata in New Caledonia is considered as a mistake.