Dendrobium nutantiflorum Hawkes & Heller (1957: 122)

Priyadarshana, Tharaka Sudesh, Atthanagoda, Anusha Gayan, Wijewardhane, Ishara Harshajith, Aberathna, Nimantha, Peabotuwage, Indika & Kumar, Pankaj, 2020, Dendrobium taprobanium (Orchidaceae): a new species from Sri Lanka with taxonomic notes on some species of the genus, Phytotaxa 432 (1), pp. 81-94 : 88-92

Dendrobium nutantiflorum Hawkes & Heller (1957: 122) . Section: Formosae. ( Figs. 7A, B ).

Type: — SRI LANKA, 1829, Macrae 69 ( K!- holotype).

Taxonomic notes: Govaerts et al. (2019) have considered D. nutantiflorum as a replacement name for D. nutans Lindl. (non C.Presl), and as a synonym of D. jerdonianum Wight. However, Hooker (1890) , Kumar & Manilal (2004) and Fernando & Ormerod (2008) have considered D. jerdonianum and D. nutantiflorum as two distinct species, which the current authors also concur with. Dendrobium nutantiflorum is distributed in India (Kerala and Tamil Nadu) and Sri Lanka, and it can be identified on the basis of having white coloured flowers and pink coloured lip ( Figs. 7A, B ). In contrast, D. jerdonianum is endemic to India (Kerala and Karnataka), and it has bright-orange coloured flowers and orange coloured lip. ( Figs. 7C, D )

Dendrobium panduratum Lindley (1858: 19) . Callista pandurata (Lindl.) Kuntze (1891: 655) . Section: Stachyobium . ( Figs. 5B–D ).

Type: — SRI LANKA. G. H. K.Thwaites 2353 ( K 000894343) ( K! - lectotype designated here).

Taxonomic notes: Lindley (1858) studied two specimens from Sri Lanka while describing D. panduratum , i.e., Hooker 147 and Thwaites 2353. Therefore, a lectotype need to be designated. We select the latter specimen, Thwaites 2353 as the lectotype, and Hooker 147 specimen could not be located.

Dendrobium trinervium Ridley (1896: 242) . Dendrobium gunnarii Rao (1992: 227) , syn. nov. Type. India , North Andaman Island , 17 December 1990, P.S.N.Rao 15791 (CAL-holotype; PBL-isotype).

Type: — THAILAND, Phang Nga, C.Curtis s.n. (SING-holotype).

Taxonomic notes: Dendrobium gunnarii from the Andaman Islands of India and D. trinervium from Indochina share similar morphological characteristics, i.e., stem 5–15 cm long, terete or slightly compressed; flowers greenish-white;

lip 3-lobed, side lobes rounded, three thickened lamellate and green-coloured callus arising from the base of the lip and ending at the epichile. Hence, D. gunnarii is synonymised under D. trinervium .

Global distribution:— Cambodia, India , Laos, Thailand and Peninsular Malaysia.

Figures

FIGURE 5. Dendrobium species in Sri Lanka, A. D. diodon, B. D. panduratum (pinkish-white colour form), C. D. panduratum (white colour form), D. D. panduratum (white with minute-pink colour form). Photo credits to Anusha G. Atthanagoda.

FIGURE 7. Dendrobium species, A. D.nutantiflorum (plant with inflorescence, Sri Lanka), B. D. nutantiflorum (close-up of inflorescence, Sri Lanka), C. D. jerdonianum (plant with inflorescence, India), D. D. jerdonianum (close-up of inflorescence, India). Photo credits to Tharaka S. Priyadarshana (A & B) and Ravee Bhat (C & D).