Dendrobium nutantiflorum Hawkes & Heller (1957: 122)

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

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 View FIGURE 7 ). 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 View FIGURE 7 )

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

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) View in CoL . Dendrobium gunnarii Rao (1992: 227) View in CoL , syn. nov. Type. India View in CoL , 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.