Desmogymnosiphon chimeicus Guinea

Emilio Guinea Lopez (1946) coined a new genus of the Burmanniaceae, Desmogymnosiphon, on the base of filiform stigmatic appendages he believed to be unique within the family. However, these appendages are frequently occuring in the genus Gymnosiphon, even in two species occuring in West Africa, where he found his specimen (Mount Chime in Equatorial Guinea). Maas-van de Kamer (1998), consequently, synonymized Desmogymnosiphon with Gymnosiphon, but since her treatment is on generic level an assessement of the specimen described by Guinea Lopez (1946) has not yet been undertaken. I, therefore, tried to compare the lines characterizing Gymnosiphon spp. of West Africa in Jonker (1938), Hepper (1968), and Maas and Maas-van de Kamer (2010) with the description and drawings of Guinea Lopez (1946). Unfortunately, the drawings are not too instructive as well as the limited data given in the description. All measurements fall within the rage of G. longistylus and G. constrictus, while G. bekensis has much larger flowers and misses the stigmatic appendages. Gymnosiphon constrictus shows a prominent constriction of the floral tube shortly beneath the perianth lobes and, hence, drops out of the options, too. Most similar is Gymnosiphon longistylus, but differences appear to be the non-trilobate outer perianth lobes of 'Desmogymnosiphon chimeicus', the margins of which are described to be eroded. Non-trilobate perianth lobes are actually a feature of the neotropical genus Hexapterella (H. gentianoides also shares the caducous perianth limb with Gymnosiphon), but Hexapterella is also characterized by a 6-ribbed floral tube and relatively long filaments (not in H. steyermarkii), both missing in the description of Desmogymnosiphon. Anyhow, beside being a (so far) neotropical taxon Hexapterella also lacks the stigmatic appendages.
In summary, G. longistylus matches best the circumscription of Desmogymnosiphon chimeicus and if we consider the eroded margins of the perianth lobes in Guinea's specimen to be remnants of the indeed narrow side lobes of Gymnosiphon longistylus, conspecificity to the latter is easily conceivable. Nevertheless, until a direct comparison of the type specimen of Guinea Lopez (1946) has been directly compared to other West African Gymnosiphon spp. we treat 'Desmogymnosiphon chimeicus' as an unassigned specimen.