Oberonia ensiformis (Sm.) Lindl.

Geiger, D. L., 2020, Studies in Oberonia 8 (Orchidaceae: Malaxideae). Additional 24 new synonyms, a corrected spelling, and other nomenclatural matters, Blumea 65 (3), pp. 188-203 : 194

Oberonia ensiformis (Sm.) Lindl. — Fig. 6

Oberonia ensiformis (Sm.) Lindl. (1859) 4. — Malaxis ensiformis Sm.(1812) Malaxis #14, [p. 180]. — Lectotype (first step designation by Ansari & Balakrishnan (1990:27): Hamilton-Buchanan s.n. (LINN-HS 1396.11.1 –2), Nepal, Narainhetty. Buchanan s.n. (questionable isolecto BM000088250), Nepal.

Oberonia vesiculifera Aver. in Aver. et al. (2019) 151, f. 1292. — Type: AL 965 /1 (holo LE 01048682 ), 300–530 m, [ Vietnam,] Nam No Npa [inferred from title]; AL 920 (para LE 01048684 ), 400–600 m, [ Vietnam,] Nam No Npa [inferred from title], syn. nov.

Notes — The identity of O. ensiformis is rather uncontroversial, despite the fact that the protologue did not contain any illustrations and that images of the type are not available. The written account of the species by Smith (1812) describing it having sword-shaped leaves with basal abscission scar and dull orange flowers with ovate sepals and petals and a fourlobed lip only matches one species occurring in India, namely what is commonly referred to O. ensiformis (e.g., Ansari & Balakrishnan 1990). Despite the long chresonymy for the species, there are surprisingly few herbarium specimens, with not a single fluid preserved sample in any institutional repository visited or contacted.

Ansari & Balakrishnan’s (1990: 27) reference to “Type: Hammilton-Buchanan s.n. ... (LINN)” constitutes a first-step lectotypification. Averyanov (2013) cited LINN as holotype, most likely not aware of the two sheets.

Averyanov et al. (2019) distinguished O. vesiculifera from O. ensiformis solely on the basis of vesicles or calli above the constriction in the middle of the lip. The presence of those calli has been documented in O. ensiformis , for which reason O. vesiculifera is an obvious synonym of O. ensiformis . It is unclear what Averyanov considered ‘ ensiformis ’. He did not refer any of his previously illustrated O. ensiformis with calli (e.g., CPC 1887 Averyanov 2013: f. 76b,c) to his new taxon.

The reporting and illustration of those calli is rather variable. They can be recognized in the photograph of Ansari & Balakrishnan (1990: pl. 2b) from India, Raskoti (2009: 191, text-fig.) from Nepal, and Averyanov (2013: f. 76c) from Vietnam. Seidenfaden & Smitinand (1959), Seidenfaden (1968, 1978), Abraham & Vatsala (1981), Pradhan (1979), Ho (1993), Chen et al. (1999), and Lucksom (2007) show them clearly on their drawings. However, usually only a single callus is evident. The otherwise exquisite colour drawing in Hooker (1858: f. 5), though misidentified as O. acaulis , and King & Pantling (1898: pl. 9) also alluded to them. The drawings in Ansari & Balakrishnan (1990) and Averyanov (2013: f. 77h) do not show a trace of those calli, but the written description in both referred to pairs of minute calli. Given the numerous demonstrated inaccuracies in drawings of Oberonia flowers ( Geiger 2019) I consider those inconsistencies are problems with drawings rather than representing additional species. SEM images always show the dual calli. The claim that the species with dual calli is microendemic to the type locality in Vietnam is demonstrably false.

Misra (2004) considered the specimens from Orissa to be distinct at the species level because of slightly different distribution of the calli on the lip. Such a statement cannot be found in the subsequent edition ( Misra 2014), which suggests that he reconsidered his earlier statement and regarded the observed differences to lie within intraspecific variability. Given the rather slight nature of differences, the details of callus morphology are taxonomically insignificant.

Figures

Fig. 6 Oberonia ensiformis. a–c. Photograph and z-stack micrographs of cultivated specimen DLG 570, HOAG 18. a. Habit; b. portion of inflorescence; c. individual flowers; d. illustrations of O. vesiculifera from Averyanov et al. (2019); e–g. SEM images of flowers; e, g. DLG 570, HOAG 18; f. DLG 572, HOAG 16. — Scale bar: e–g = 1 mm.