Oberonia subligaculifera J.J.Sm., Bull. Jard. Bot. Buitenzorg

D. L., Geiger, M., Sulaiman & Murugan, C., 2021, Studies in Oberonia 10. A re-evaluation of Oberonia brachystachys and O. subligaculifera (Orchidaceae: Malaxideae) and their synonyms, Rheedea 31 (3), pp. 141-160 : 152-156

Oberonia subligaculifera J.J.Sm., Bull. Jard. Bot. Buitenzorg , sér. 2, 9: 35. 1913. Holotype: INDONESIA, Java, Jawa Barat, near Tirtasari , 1500 m, J.J. Smith & Rant 201 (repository unknown).

Oberonia bambusicola Kerr, Bull. Misc. Inform. Kew 1927: 213 . 1927. Syntype: THAILAND, Chon Buri, Sriracha [= Si Racha], Nang Khaw, 50 m, Kerr 383 (K [ K000596096 ]!).

Oberonia evrardii Gagnep., Bull. Soc. Bot. France 76: 326. 1929. Lectotype: (inadvertent designation by Seidenfaden, 1968: 48 by reference to “P!, type”): VIETNAM, Lam ÐÑng, Dalat , chalet Rimaud, 28.10.1920, Evrard 300 (P [ P00404954 ]!).

Oberonia kanburiensis Seidenf., Bot. Tidsskr. 68: 47. 1973. Type: THAILAND, Kanchanaburi, West of Siswat, Hauy Ban Kao, Beusekom et al. 3657 (holo C ( C2103 ) n.v., iso L [ L0061749 ]!).

Oberonia arunachalensis A.N.Rao, Rheedea 7: 130. 1997. Type: INDIA , Arunachal Pradesh, Lohit district, Kamlang Reserve forest on way to

Chamba-glowlake area, 500 m, A.N. Rao 28067 (holo OHT n.v.). syn. nov.

Oberonia raoi L.R.Shakya & R.P.Chaudhary, Rheedea 10: 57. 2000 [“ raoii ”]. Type: INDIA , Meghalaya, Khasia hills, Nongpoh , 4000 ft. ( 1219 m), August 1897, Pantling s.n. (holo CAL [ CAL0000024756 ]!). Erroneous citation of type gathering in protologue, see below. syn. nov.

Oberonia kamlangensis A.N.Rao, J. Econ. Taxon. Bot. 24: 267. 2000. Type: INDIA , Arunachal Pradesh, Lohit district, Kamlang sanctuary, 150 m, A.N. Rao 28283 A (holo OHT n.v.) ; ibid, A. N . Rao 28283- B (para CAL n.v.) ; ibid. A. N . Rao 28283- C (para OHT n.v.) . syn. nov. FIGS. 6 & 7

Epiphytic herbs, usually 4–6 leaves, jointed, forming stemless fan. Leaves narrow elongated acuminate, acute, typically slightly falcate towards or away from growth axis, typically 2–8 cm long, 0.3–0.5 cm wide. Roots thin, fibrous, unbranched. Inflorescence typically 5–10 cm long, typically 2– 3 × as long as leaves. Scape short, rachis longitudinally grooved, flowers variable arranged from distinct whorls, to in spiral, or scattered. Flowers 2.0–2.5 × 2.2–3.0 mm, average ~2.5 × 2.5 mm, green, yellow-orange, orange. Bracts, elongated acuminate, acute, erose, about as long as flower. Pedicelled ovary round, ~2.0– 2.5 mm long. Orientation of all tepals somewhat forward or somewhat recurved. Sepals broad oval acute. Petals oblong obtuse, erose to dentate or laciniate. Lip four-lobed, lateral lobes square or trapezoidal, margin erose to dentate; mesochile more or less constricted, entire; epichile lobes truncated, rounded or sub-quadrate, margins dentate or erose, disc indistinct, sac unknown.

Flowering: Flowering throughout year with peaks in February and October ( Fig. 7a ). The gap in June– July is considered a data artifact.

Habitat: Erect or pendulous epiphyte, evergreen to deciduous, broad-leaf, mixed and conifer forest, on branches of tree and shrubs, on bamboo, in coffee plantation, 0–2400 m, predominantly below 900 m ( Fig. 7a ).

Distribution: India , Malaysia, Myanmar, Thailand, Vietnam, China, Indonesia, Philippines (Luzon) ( Kerr, 1927; Santapau & Kapadia, 1960; Backer & Bakhuizen van der Brink, 1968; Seidenfaden, 1968, 1978; Saldanha in Saldanha & Nicolson, 1976; Pradhan, 1979; Abraham & Vatsala, 1981; Manilal, 1988; Comber, 1990; Naithani, 1990; Sakkar, 1995a; Turner, 1995; Hop, 1998; Bose et al., 1999; Averyanov & Averyanova, 2003; Kumar & Manilal, 2004; Rao, 2010; Averyanov, 2013; Bunpha et al., 2013, 2019; Jin et al., 2019; herbarium records).

Specimens examined: INDONESIA, Java, Bandong, Zollinger 897 (P[P00428170: left]). Sumatra, Gunung Leuser Nature Reserve, Atjeh, Ketambe valley of Lau Alas, near tributary of Lau Ketambe, de Wilde & de Wilde-Duyfjes 12267 (K). MALAYSIA, Sarawak, Marudidistrict between Bario and Pa Umor, Beaman 11256 (K). MYANMAR, King Lung, MacGregor 822 (E [E00616243]). PHILIPPINES, Luzon, Cordillera Administrative Region, Bontoc. Vanoverbergh 3828 (F [F452930], MO [MO799960]). THAILAND, Mae Hong Son, Khun Yuam, Larsen & Larsen 34115 (K). VIETNAM, Ha Lang, Thanh Nhat, 42 km E of Cao Bang, Averyanov CLB 732 (MO [MO04970868]). Noh Quan, Cuc Phuong National Park, CP146; Cuong et al. 775 (MO [MO5336640]).

Notes: The repository of the holotype of O. subligaculifera J.J.Sm. is unknown. The specimen is a holotype as the protologue specified that it was based on a single specimen. The species ( Fig. 6a ) and its previous recognized synonyms ( Geiger, 2019) O. evrardii ( Fig. 6d,e ) and O. kanburiensis ( Fig. 6 f, g ) is characterized by the elongate acuminate jointed leaves, the larger flowers (1.8–2.5 × 2.2– 3.0 mm), petals with strongly erose to incised margins, the four lobed lip with strongly erose to incised lateral lobes, a constriction of the entire mesochile, and a bifid epichile with erose to incised tips. Although the flowers are very similar to those of O. brachystachys , the jointed leaves of O. subligaculifera (unjointed in O. brachystachys ) in combination with the typically larger flowers indicate that they are distinct species. While intraspecific variability is extensive in Oberonia , the jointed vs. unjointed leaves have never been suggested as variable within species. On the contrary, that character has been used to separate the genus Oberonia into two subgenera ( Schlechter, 1911): Oberonia s.s. [= Apothemnophyllum Schtr.] with jointed leaves, and Menophyllum Schltr. with unjointed leaves.

Bunpha et al. (2019) considered O. evrardii distinct from O. subligaculifera based on differences in the depression of the lip and the shape of the rostellum. Neither of those characters were illustrated, and the sample size for those two species were four and five, respectively. The difference is at best subtle, with significant intraspecific variability demonstrated previously ( Geiger, 2019). Those characters are considered insignificant. The shape of the rostellum is likely affected by ontogeny and state of maturation, hence, is meaningless.

Oberonia bambusicola Kerr ( Fig. 6b,c ) had been considered a synonym of O. brachystachys ( Seidenfaden, 1968; WCSP, 2020), but is here placed in synonymy with O. subligaculifera . The shared characters between O. bambusicola and O. subligaculifera include the jointed leaves (visible in K syntype), the size of the flowers (> 3 mm), the greenish flower color (in fluid preserved specimen), the erose petals, and all aspects of the lip. It differs from O. brachystachys by the jointed vs. unjointed leaves, the larger flowers (> 3 mm vs. ~ 1.5 mm), and the flower color (green vs. red). While the size of the flower was not given by Kerr (1927), it can be inferred by adding his measurements of the lip ( 2.2 mm long) and the sepal ( 1.5 mm long).

Kerr (1927) compared his species only to O. recurva and noted the proportionally shorter lip and the less erose petals. The annotations by Kerr preserved on the type sheet identify his specimen as cf. O. brachystachys , a further indication to the synonymy of O. brachystachys and O. recurva discussed above. He did not mention O. subligaculifera .

Oberonia arunachalensis ( Fig. 6h,i ) is a synonym of O. subligaculifera . It shares the fan-shaped habit, the jointed leaves (according to protologue, not evident in figure), the oval and erose petals, and the lip shape with serrated lateral lobes and epichile lobes with O. subligaculifera . The two names refer to the same species. Rao (1997) compared his O. arunachalensis only with O. kanburiensis , and distinguished the two by the longer leaves and inflorescence (both extensively variable within species), green flowers (no difference), elliptical-elongate petals (no difference) and dentate lobes of the lip (no difference). Accordingly, the differentiation was based on lack of knowledge of intraspecific variability and outright mistakes.

The flowers appear to be rather small ( c. 1.7 × 1.4 mm) based on the scale bar associated with the flower. Errors in scale bars and drawings are abundant in micro-floral orchids ( Geiger, 2019). According to the scale bar of the entire flower ( Rao, 1997: fig. 1d) the bract is 1.3 mm long, while the isolated bract shown in Rao (1997: fig. 1e) is 1.5 mm long based on its scale bar. Whether this should illustrate variability of floral parts on the same inflorescence or whether those are scale bar errors is unclear. Even with a 15% variance in measurement accuracy, the flowers of O. arunachalensis would be rather small for O. subligaculifera and more compatible with O. brachystachys . Intraspecific variability of floral size by up to 50% have been documented in other species ( O. complanata : Geiger, 2019; O. equitans : Geiger et al., 2020); O. arunachalensis falls within that documented range of intraspecific variability with respect to O. subligaculifera . The jointed leaves according to protologue, not shown in Rao (1997: figs. 1c; fig. 6h), in addition to the more eastern type locality is indicative of a synonymy with O. subligaculifera .

The protologue of O. raoi misspelled the specific epithet as raoii, an error already noted by Badyopdhyay et al. (2016). The protologue further mistook an old herbarium ledger number [449798] as the gathering number of the type; the correct citation of the gathering is Pantling s.n.

Oberonia raoi ( Fig. 6j,k ) is a synonym of O. subligaculifera . The common characters include the habit with jointed leaves, the erose margins of the ovate petals, the overall shape of the lip, and the erose margin of the square lateral lobes at right angle to the axis of the lip. The only character not matching are the margins of the apical lobes of the lip, which are distinctly erose in O. brachystachys while appearing entire in the drawing of O. raoi . However, the quality of the drawing is not particularly good and one may wonder whether artistic license missed those small details. Given the large number of matching details including the jointed leaves, O. raoi is here synonymized under O. subligaculifera . Oberonia raoi was only compared to O. myriantha (= O. acaulis ) and not to O. subligaculifera .

Oberonia kamlangensis ( Fig. 6l,m ) is a synonym of O. subligaculifera . It was compared to O. mucronata (D.Don) Ormerod & Seidenf. in G.Seidenf., but not to O. subligaculifera or to O. arunachalensis described by the same author three years earlier ( Rao, 2000). It is another case where a new species is justified by comparison to a very distant and different species while the more similar species were not considered. Oberonia kamlangensis is indistinguishable from O. arunachalensis , itself a synonym of O. subligaculifera . The jointed leaves, the strongly erose petals, and the lip with strongly laciniate lateral lobes and the equally deeply incised epichile lobes ( Fig. 6h,l,m ) are shared by the two nominal species.

The flower color was given as pale yellow-green by Smith (1913), but the description was based on ethanol-preserved material. Ethanol bleaches the flower color (Geiger, pers. obs.) with orange flowers turn yellow green. Green flowers have been reported by Rao (1997: as O. arunachalensis ). Variability in flower color from green to orange is well-known in O. mucronata ( Geiger, 2019) .

Figures

FIG. 6. Drawings and photographiC image of Oberonia subligaCulifera J.J.Sm. and its synonyms: A. O. subligaCulifera illustration by J.J. Smith from SChuiteman and de Vogel (2006), entire flower and isolated lip; b,C. O. bambusiCola Kerr 383 (syntype K [K000596096]); b. Drawing of flower and lip on note affixed to type sheet; C. Habit; D,e. O. evrardii Gangnep.; D. Drawing of leCtotype Evrard 300 (P [P00404954]) by Seidenfaden (1968: fig. 27); e. Drawing on leCtotype sheet of entire flower, isolated lip, and isolated petal; f,G. O. kanburiensis Seidenf. drawing of type from Seidenfaden (1978: fig. 9); f. Flower; G. Habit; h,I. O. arunaChalensis A.N. Rao drawing from Rao (1997: fig. 1); h. Habit; I. Flower; j,k. O. raoi L.R. Shakya and R.P. Chaudhary drawing from Shakya and Chaudhary (2000: fig. 1); j. Habit; k. Flower; L,m. O. kamlangensis A.N.Rao drawings from Rao (2000:pl. 1); L. Habit;m. Flower parts digitally rearranged to natural positions;(a,d, f–m from Cited publiCations under fair use provision of Copyright law; photos b,C,e by D.L. Geiger).

Fig. 7. Summary bar Charts of eCologiCal data for Oberonia subligaCulifera J.J.Sm., Compiled from any of its synonyms: A. Phenology data from Smith (1913), Santapau and Kapadia (1960), Saldanha and NiColson (1976), Abraham and Vatsala (1981), Manilal (1988), Ansari & Balakrishnan (1990), Nayar et al. (2006), Bunpha et al. (2013, 2019), Jin et al. (2019), herbarium reCords; b. Elevation data from Smith (1913), Kerr (1927), Ansari and Balakrishnan (1990), Seidenfaden (1992), Rao (1997), Averyanov et al. (2000), Averyanov and Averyanova (2003),Averyanov (2013), Bunpha et al. (2013, 2019), Jin et al. (2019), herbarium reCords; (graphiCs by D.L. Geiger).