Gymnosiphon longistylus (Bentham) Hutchinson ex Hutchinson and Dalziel
Firstly described by Bentham (1849) as Dictyostega longistyla, transferred to Gymnosiphon longistylus by Hutchinson in Hutchinson and Dalziel (1936), accepted by Jonker (1938) and Maas and Maas-van de Kamer (2010). Its synonym Gymnosiphon squamatum (Wright 1897a), little later corrected to Gymnosiphon squamatus (Wright 1897b), was changed to Ptychomeria squamata by Schlechter (1921), but merged with G. longistylus by Jonker (1938).
According to the entry in Hutchinson and Dalziel (1936), the transfer to Gymnosiphon longistylus should have been appeared in Kew Bulletin 1936 (entry: "G. longistylus Hutch. in Kew Bull. 1936: ined.") but was probably cancelled (I, indeed, could not find any appropriate publication around that date and in that journal). IPNI (The International Plant Names Index), as well, cite Hutchinson and Dalziel (1936) with the addtion 'in clavis', for the diagnosis is only included in the key to G. longistylus vs. G. congestus (today Campylosiphon congestus).