Gastrodia gunatillekeorum, a new species in the family Orchidaceae, is described and illustrated from a tropical lowland rainforests of Sri Lanka. It is morphologically close to G. spatulata which is endemic to Indonesia owing to the white flower front with yellowish-orange colour on the inner wall of perianth tube and free part of perianth tube reflexed backwards. However, these two species can be very well differentiated on the basis of spathulate to linear petals which are shorter than sepals, fused only at the base and present inside the perianth tube; labellum elongate-elliptic and column broadest in the middle part in G. spatulata, whereas petals as long as sepals with apical 1/3rd part free (rest fused with sepals) and reflexed backwards, labellum rhomboid in shape, column broadest towards the apex in G. gunatillekeorum. Taxonomic account, line drawing, color photographs and conservation assessment are provided for the new species.

A new species, Dendrobium taprobanium (Orchidaceae), is described and illustrated from the Sabaragamuwa Province in Sri Lanka. The new species is morphologically similar to D. trinervium from Indochina. However, it can be readily distinguished by having a rounded callus with fine glandular hairs at the seam of the hypochile and epichile, while D. trinervium has three rows of thickened glabrous calli arising from the middle or posterior end of the lip and extending to the apex of the midlobe. Due to its morphological similarities, D. gunnarii, an endemic orchid from the Andaman Islands, India, is synonymised to D. trinervium. Additionally, taxonomic notes are also provided for D. heterocarpum, D. macrostaychum and D. nutantiflorum, and a lectotype is designated for D. panduratum. A key to all the Dendrobium species in Sri Lanka is provided along with colour photographs.

Pteroceras dalaputtuwa, a new species, is described from the lowland-wet zone of Sri Lanka. For the first time in the history of plant nomenclature, a new species is named after an elephant, ‘Galgamuwa Dala Puttuwa’, which was killed for its majestic ivory. The new species shows a close morphological affinity with P. philippinense from the Philippines. However, P. dalaputtuwa sp. nov. can be readily distinguished by having small and partially opened flowers (10 mm long × 5 mm wide), short petals (4 mm long × 1 mm wide), short sepals (4.9 mm long × 3.0 mm wide) and elongated rectangular-oval spur (7 mm long × 3 mm wide). P. viridiflorum, which is considered as a “Critically Endangered Possibly Extinct” [CR(PE)] orchid, is also re-collected after after a gap of nearly 150 years with a record of a new colour form (white colour variant) and, is re-described with designation of a lectotype and an epitype.

A new species, Podochilus warnagalensis is described from Adam’s Peak Nature Reserve, Sri Lanka. A key to all species of the genus Podochilus found in Sri Lanka is provided.

Oberonia meegaskumburae is described and illustrated from Adam’s Peak (Samanala) Nature Reserve, Sri Lanka and differentiated from its close ally, O. weragamaensis on the basis of larger flowers (3 mm long) in former against smaller (2 mm) in latter; longer floral bracts (1.9 mm) in former against shorter (1 mm) in latter; equal size (> 0.2 mm) of lobules of mid-lobe in former against shorter mid-lobule (< 0.1 mm) in latter; slender, terete and club-shaped tip of lateral lobe curved to face each other in former against sub-triangular, parallel and inflated in latter. Key to all species of genus Oberonia found in Sri Lanka is provided.