Xyris seubertii L.A.Nilsson, Kongl. Svenska Vetenskap.-Akad. Handl. 24(14): 51. 1892.

Wanderley, Maria das Gracas Lapa, 2017, Typification of binomials in Xyris section Nematopus (Xyridaceae) published by L. A. Nilsson, PhytoKeys 80, pp. 65-76 : 72

12. Xyris seubertii L.A.Nilsson, Kongl. Svenska Vetenskap.-Akad. Handl. 24(14): 51. 1892.

Type.

Guyana: "British Guiana", Rich. Schomburgk 897 (in herb. Berol.) (holotype: B! [B10 0242218]; isotype: K! [K000308887]).

In his species description, Nilsson (1892) cited the collection Schomburgk 897, originating from British Guiana, undated, and deposited in the B herbarium. The unicate of this collection in B (B10 0242218) was examined, and is compatible with the protologue. Smith and Downs (1968) cited this sheet (B10 0242218) as “type”, thus identifying it as the holotype, which has two plants with the typical characteristics of Xyris seubertii , and the label indicates the location and the date (October 1842), as quoted in the protologue. Illustrations attached to the holotype sheet show characteristic features of the species, with a drawing of the central placenta and sepals with a thickly pilose carina and acute apex. However, in addition to these illustrations, there is an annotation signed by Seubert that indicates the species as Xyris fontanesiana Kunth, now considered as a synonym of Xyris anceps Lam. ( Xyris section Xyris ), which has a marginal placenta and is very different from X. seubertii ( Xyris section Nematopus ). An isotype is deposited at K (K000308887), with an annotation giving its origin from Guiana, and with indications of having previously been separated from another specimen. Another sheet at K (K000308888), also of Xyris seubertii , has the locality information "Roraima Expedition, British Guiana, Monte Roraima". The collector is not mentioned, but the number 257 given on the label makes clear that it does not belong to the type collection.