Timonius billitonensis Valeton (1909a: 59)

Chen, Junhao & Wong, Khoon Meng, 2020, Typification and nomenclatural notes on Bornean Timonius (Rubiaceae: Guettardeae), Phytotaxa 446 (2), pp. 114-120 : 115

Timonius billitonensis Valeton (1909a: 59)

Type: — INDONESIA. Bilitoeng, Mangar, sin. dat. (♂), Teijsmann s.n. (lectotype BO [No numerical identifiers found on the sheet], designated here).

Notes: — Three syntypes are indicated in the protologue: Teijsmann s.n. and Ham s.n. from Billiton Island, and Hallier 2444 from Mount Kelam in West Kalimantan (“Borneo Centralis in monte Klam” fide Valeton (1909a)). Unlike the Billiton collections, the calyx morphology of Hallier 2444 from Borneo is inconsistent with the protologue—the length of the calyx and its lobes are much shorter than that stated in the protologue. Moreover, it is different from the Billiton collections by its subglabrous calyx and non-glaucous, glabrous lower leaf surfaces, and is here excluded from the circumscription of T. billitonensis . Only the staminate inflorescence was described in Valeton’s protologue, with a note indicating that the pistillate counterpart was unknown. We identified four relevant sheets from Billiton Island in BO (where Valeton worked from 1892 to 1913): a fruiting collection with both “ Ham 19 ” and “ Burger 15 ” on its label, a sterile sheet labelled only as “ Ham 19 ”, a sterile sheet with both “ Ham 19 ” and “ Teysm. ” written on the label, and a collection by Teijsmann (without collection number) that represents the only staminate specimen. Thus, T. billitonensis is here lectotypified by the Teijsmann collection.