Trichoglottis longifolia Atthan., C. Bandara, N.L. Bandara & Kumar, 2022

Bandara, Champika, Atthanagoda, Anusha Gayan, Bandara, Nadeesha Lewke, Ranasinghe, Bhanuka & Kumar, Pankaj, 2022, Trichoglottis longifolia (Orchidaceae: Epidendroideae: Vandeae: Aeridinae), a new species from Sri Lanka, Phytotaxa 567 (1), pp. 71-78 : 72-78

Trichoglottis longifolia Atthan., C. Bandara, N.L. Bandara & Kumar sp. nov. ( Figs. 1 A–C , 2 & 3 )

TYPE: SRI LANKA. Sabaragamuwa Province, Kegalle District, Aranayaka, Maligakande , 1000 m, 29 April 2022, AKAG 29.2022 (holotype PDA!; isotype PDA!-spirit) .

Diagnosis: Trichoglottis longifolia is similar to T. tenera , but it can be easily distinguished from the latter in having longer leaves, 7‒8 cm (vs. shorter leaves, 2.5‒4.5 cm); yellowish-green flowers (vs. brownish-green); longer floral bract, 2.5‒3 mm long (vs. shorter floral bract, 2 mm long); narrow sepal, 3 mm wide and petals, 2 mm wide (vs. broad dorsal sepal 4 mm wide and petals 3.5 mm wide) and longer spur length, 5 mm (vs. shorter spur length, 3 mm).

Epiphytic herb. Roots numerous, 1.5‒2 mm thick, flexuose, greyish, glabrous, usually arising opposite to the leaf base. Stem elongated, 10‒90 cm long, 2‒3 mm thick, greenish, pendulous, sparsely branching; internodes 1.6‒3 cm. Leaves narrowly lanceolate, 6.5‒8 cm × 1.2‒1.6 cm, distichous, apex obliquely bi-lobed, longer lobule 1 mm In length, shorter lobule 0.5 mm length, both with a mucro; midrib extended to a pointed setae in between lobules, 0.2‒0.3 mm long. Inflorescence arising from stem through the leaf sheaths of internodes, 2 (rarely 3‒4) flowered racemes. Peduncle stout, terete, 1‒2 cm long. Pedicel and ovary ca. 1 cm long, curved, twisted longitudinally, glabrous. Flowers widely opened, 1.8 cm across, yellowish-green; occasionally, base of the dorsal sepal and petals sparsely dotted with brown spots. Floral bracts ovate, 2.5 mm long, 1.5 mm broad, acute, concave. Dorsal sepal lanceolate, 11 × 3 mm, narrowly obtuse, 3-veined, broadest between centre and apex. Petals linear-elliptic to linear-oblanceolate, 9 × 2 mm, obtuse, 3-veined. Lateral sepals oblique-falcate, 8 × 3 mm, apex rounded, 3-veined. Labellum 7 × 5 mm (length from the base of column to the apex of median lobe), firmly attached to the column, spurred, 3-lobed with indistinct elongate fleshy lateral lobes and large median lobe; lateral lobes erect, quadrangular, 3 × 2 mm, crenulate to retuse, white with thick red veins; median lobe faintly 3-lobulate, glabrous, fleshy, white with red spots towards the margin; side lobule almost rhomboid in outline, 3-lobules rounded. Spur 5 × 1.5 mm, apex rounded, hairy on the inner margin with a bifid callus arising from the back wall of spur and ending at the throat, ca. 1.5 mm. Column 3 × 2.5 mm, stout, erect, broadly cylindric, extended into a short, inconspicuous foot. Rostellum small, bifid, ca. 1 × 0.5 mm. Operculum hemispherical, 1–1.2 mm wide, 0.1–0.2 mm long, with a small beak. Anther terminal, 2 loculed, 1.8 × 2 mm. Pollina 2, 0.5 × 0.4 mm each, completely divided into densely appressed subequal hemispheric pollinia; stipe 0.7–0.8 mm long; viscidium ovate, about 0.2 mm long. Ovary and pedicel clavate, 7 mm long. Capsule fusiform or narrowly ellipsoid to cylindric in shape, dull greenish, strongly ribbed, 2.4‒3 × 0.8‒1 cm.

Phenology: Trichoglottis longifolia flowering from April to July and fruiting from May to August.

Distribution: Trichoglottis longifolia is known from Aranayaka, (Kegalle District) and Bambarabotuwa, Kuruwita, Palabaddala and Samanala Nature Reserve (Ratnapura District) in Sabaragamuwa Province.

Etymology: Referring to the long leaf of the species in comparison to its allied species in Sri Lanka.

Habitat and ecology: Trichoglottis longifolia is an epiphytic orchid which grows on the tropical sub-montane forests between 910‒1200 m elevation. The host plants are Litsea longifolia (Nees) Trimen , Syzygium sp. and bamboo species; growing 1‒3.5 m above from the ground in shady habitats and associated with Adrorhizon purpurascens (Thwaites) Hooker , Dendrobium panduratum Lindley , Diploprora championii (Lindley) Hooker , Oberonia scyllae Lindley , Phreatia jayaweerae Ormerod and Polystachya concreta (Jacquin) Garay & H.R. Sweet.

Conservation status: In Kegalle, there are few subpopulations consisting of approximately 150 mature individuals and in Rathnapura subpopulation consists of <50 mature individuals. However, only <10 individuals in the Bambarabotuwa subpopulation. Based on current knowledge, the Extent of Occurrence (EOO) and Area of Occupancy (AOO) estimated using GeoCAT ( Moat 2007) as ~ 390 km 2 and 20 km 2 respectively. No threat is known for this species, except for some minor habitat disturbance due to landuse changes. With 5 subpopulations, comprising less than 250 mature individuals, Trichoglottis longifolia can be solely assessed based on its small population size, as Endangered (EN: D) following IUCN guidelines ( IUCN 2019).

Additional specimens examined: Trichoglottis tenera : — SRI LANKA. NUWARA ELIYA DISTRICT : Nuwara Eliya, Aug. 1962, Jayaweera 2192 ( PDA!); Hakgala , Mar. 1889, W. Nock s.n. ( PDA!); Punduluoya , Feb. 1973, Cramer 4067 ( US!-00506216); along road Kandy to Nuwara Eliya, May 1978, D.D. Soejarto 4876 ( US!- 00506217, L!- L.1529312, P!- P00361712 ); BADULLA DISTRICT: Namunukula, Mar. 1907, J. M. Silva s.n. ( PDA!); LOCALITY UNKNOWN: 1829, Macrae 66 ( K!- K000895724 , holotype); Macrae s.n. ( K!- K000974382 ); Macrae s.n. ( K!- K000974383 ); Thwaites C. P. 2983 ( PDA!); Walker 118 ( PDA!); 1869, Thwaites C. P. 2983 ( P!- P00361710 ) ; 1854, Thwaites C. P. 2983 ( P!- P00361711 ). INDIA. Grands bois à Neddoubitta, Jan. 1841, L. Claude s.n. ( P!- P00361713 ). Trichoglottis longifolia : — SRI LANKA. RATNAPURA DISTRICT : Seethagangula , Kuruwita-Eratne trail, Samanala Nature Reserve, May 2022, AKAG 30.2022 ( PDA!) .

Taxonomic Notes: Trichoglottis longifolia is morphologically similar to T. tenera , but it can be easily distinguished from the latter by having 7‒8 cm long leaves, yellowish-green flowers, lanceolate dorsal sepal and petals and 5 mm long spur. Both species are uniquely distributed in separate forest regions. T. tenera is confined to the tropical montane and sub-montane forests above 1200 m elev. while, T. longifolia in tropical sub-montane forests between 910‒1200 m elevation.

Figures

FIGURE 1. Trichoglottis longifolia Atthan., C. Bandara, N.L. Bandara & Kumar sp. nov. A. Plant habit. B. Front view of flower. C. Side view of flower. Trichoglottis tenera D. Plant habit. E. Front view of flower. F. Side view of flower. Photographs by Anusha Gayan Atthanagoda.

FIGURE 2. Trichoglottis longifolia Atthan., C. Bandara, N.L. Bandara & Kumar sp. nov. A. Plant habit. B. Front view of flower. C. Side view of flower. D. Bract. E. Dorsal sepal. F1 & F2. Petals. G1 & G2. Lateral sepals. H. Labellum. I. Side view of labellum. J. Sagittal section of labellum and spur. K. Side view of column and spur. L. Leaf. M. Capsule. N. Operculum. O. Pollinia. Photographs by Anusha Gayan Atthanagoda.

FIGURE 3. Trichoglottis longifolia Atthan., C. Bandara, N.L. Bandara & Kumar sp. nov. A. Plant habit. B. Front view of flower. C. Side view of flower. D. Bract. E. Dorsal sepal. F1 & F2. Petals.G1 & G2. Lateral sepals.H. Labellum. I. Side view of labellum.J. Sagittal section of labellum and spur. K. Leaf. L. Side view of column and spur. M. Front view of column and spur. N. Operculum. O. Pollinia P. Capsule. Illustrations by Champika Bandara.