Benthamia rostrata

Hervouet, Jean-Michel, Descourvières, Pascal, Hermans, Johan & Longou, Ludivine, 2025, Revision of the genus Benthamia A. Rich. (Orchidaceae, Orchidioideae, Habenariinae), Adansonia (3) 47 (11), pp. 171-249 : 247

B. rostrata , appear to be embedded in Cynorkis according to Ngugi et al. (2020). This was acknowledged by Pailler et al. (2024) who reinstated the name Cynorkis micrantha , this species being close to Benthamia exilis .

Benthamia glaberrima seems related to the genus Peristylus Blume , e.g. to Peristylus constrictus (Lindl.) Lindl. from Asia, but this may be only a convergence. Nevertheless, Peristylus affinis (Don) Seidenf. from Asia can morphologically hardly be distinguished from the core group of Benthamia . Peristylus goodyeroides (Don) Lindl. would also be considered a Benthamia , if it would occur in Madagascar, since the column has prominent basal auricles. Peristylus is a genus closely related to Habenaria . It would be good to include it in further molecular analysis studies and given its variability it also needs a revision.

Lastly, Oligophyton H.P.Linder , from the Chimanimani Mountains in Zimbabwe, should also be investigated. Its single species Oligophyton drummondii H.P.Linder & G.Will. was transferred to Benthamia as B. drummondii (H.P.Linder & G.Will.) Rutkowski & Szlach. and could belong here although, in the protologue, Linder & Williamson (1986) argued that it is different from Benthamia and Peristylus .

We hope this revision will provide a safe ground to further studies, including molecular analysis, aiming at circumscribing genera Benthamia , Cynorkis , Habenaria , Peristylus and Tylostigma .

Molecular analysis would be also useful to give a closer look at very variable species such as Benthamia africana and B. erinacea , each one with disconnected distribution ranges.

NOTE Benthamia mamilyae L.Rapp & Hermans was published ( Candollea 80: 110, 2025) just before the final publication of the present paper and could not be taken into account.