Chiloschista shanica K.P.Wojtas, C.Bandara & Kumar, 2023

Wojtas, K. Philip, Bandara, Champika & Kumar, Pankaj, 2023, A new species of Chiloschista (Orchidaceae, Aeridinae) from Myanmar, Phytotaxa 612 (1), pp. 57-66 : 58-65

Chiloschista shanica K.P.Wojtas, C.Bandara & Kumar , sp. nov.

TYPES: Plants obtained from Thailand and introduced as in vitro culture to Germany, flowered in cultivation, January and February 2023 , K. P.Wojtas KPW230115-1 ( HEID207662 — Holotype); Isotypes: KPW230114-1 ( HEID207661 ), KPW230122-1 ( HEID207663 ), KPW230212-1 ( HEID207664 ) and KPW230224-1 ( HEID207665 ) ( HEID!, specimens preserved in spirit). ( Figs. 1 , 2 , 3 ) .

Diagnosis: Chiloschista shanica resembles a Thai endemic C. rodriguezii however, former differs from latter in having green coloured peduncle and pedicel with brownish streaks; flowers densely placed on peduncle; sepals and petals white coloured dotted with reddish-brown spots and are almost glabrous on both surfaces and margin; dorsal sepal (6 × 5 mm), lateral sepals (6 × 6 mm) and petals (5.5 × 5.5 mm) shorter and wider; labellum sac pointed forwards, side lobes of labellum acute with denticulate margin and arching above the column; upper margin of rostellum denticulate. While, in C. rodriguezii ( Fig. 4 ) peduncle and pedicel is green with red marking only towards the base; flowers distantly placed on peduncle; sepals and petals pale yellowish green coloured, hairy on the external surface; dorsal sepal (7 × 4 mm), lateral sepals (7 × 4 mm) and petals (6 × 3 mm) longer and narrower; labellum sac pointing downwards, side lobes of the labellum with rounded apex, margin entire and not rising above column and upper margin of rostellum ciliate. Furthermore, C. shanica can be distinguished from it’s another ally, C. parishii , based on large flowers (1.4–1.5 cm across); petals and sepals white coloured with reddish-brown spots; petals and sepals glabrous on the dorsal surface and sparsely ciliate on the margin. However, in C. parishii flowers are smaller (1.2–1.3 cm across); sepals and petals yellow with brown-red spots, dorsal surface of sepals and petals with dense hairs, but not ciliate along the margin. Chiloschista shanica can also be differentiated from C. lunifera (sensu Reichenbach 1868, see type drawing in Fig. 5 and images of live plants in Fig. 6 ) for having overlapping sepals and petals that are obovate, white coloured with reddish-brown spots on pale brown background, dorsal surface nearly glabrous; petals stretched sideways; saccate spur of labellum horrizontally angular on the apex; side lobes of the labellum falcate with slightly denticulate upper margin, inner surface with pink vertical streaks and spots in former, while sepals and petals are nonoverlapping, elliptic to oblong, yellow coloured with a distinct brown patch in the centre of each and dorsal surface puberulous throughout; petals stretched backwards; saccate spur of the labellum rounded; coloured sepals and petals with a distinctive brown area in the middle and are puberulous on their surface, ciliate along their margin; side lobes of the labellum almost rounded with entire margin, inner surface with brown streaks and spots in latter.

Description: Herb, monopodial, epiphytic with many long, smooth, terete to slightly flattened, silvery-green roots, up to 13 cm long, 2.8–3.5 mm wide and 1.5–2.0 mm thick. Stem, short, 0.8–1.0 cm long with perulate tip. Leaves not seen on flowering plants (most likely to be absent). Inflorescence racemose, ca. 7.5 cm long, pendulous, puberulous, green to brownish streaks, bearing up to 6 flowers on the studied specimens (but plants shown by Tun (2014) bear more than 20 flowers on much longer inflorescence); peduncle ca. 3.5 cm long, 0.8–1.4 mm in diameter, with one sterile peduncular bract, narrow towards the base, gradually thickening towards apex; rachis ca 4.0 cm long; floral bracts narrowly triangular, 2.0– 2.5 mm long, acute. Pedicel with ovary clavate, 0.5–0.6 cm long, 0.7–1.0 mm in diameter, villose, slightly ridged on surface. Flowers open acropetally, increases slightly in size after anthesis and last for several weeks, ca. 1.4–1.5 cm in diameter, sepals and petals white with reddish-brown spots on a slightly paleyellow background, spots larger towards center smaller towards margin, sometimes overlapping, internally puberulent, with very sparse hairs at the base and/or veins or almost glabrous, hispid externally along the column foot, lip almost white, with characteristic crimson marked side lobes, slightly scented. Dorsal sepal obovate, slightly concave, ca. 0.6 × 0.5 cm, obtuse to nearly blunt, entire, sparsely ciliate along the margin, slightly wavy towards the apex. Lateral sepals obliquely obovate, ca. 0.6 × 0.6 cm, obtuse, fused basally along the column foot, sparsely ciliate along the margin and towards the basal half on inner surface, glabrous on outer surface. Petals obliquely obovate, 5.5 × 5.5 mm, obtuse to almost rounded, ciliate along the margin. Labellum 3.5–4.0 mm high, 1.5–2.0 mm wide, attached just before the apex of the column foot, motile, base deeply saccate with hairs on the inner side, hairs glandular and longer on the back wall, shorter and eglandular on the front wall, sac 2.6–2.7 mm wide, 2.5–2.8 mm high, hairy inside, glabrous outside, slightly grooved longitudinally at the base, 3-lobed, lobes not spreading; mid lobe triangular, ca. 1 mm long, 1.0– 1.5 mm wide, obtuse, slightly folded along the midrib and arched forward, almost white; side lobes falcate, 1.2–1.3 mm long, 0.9–1.0 mm wide, acute, with slightly denticulate upper margin, lower margin entire, white with vertical streaks and spots in pink. Column stout, ca. 1 mm long and 2.5 mm wide, column foot scabrid, sparsely hairy on both edges; rostellum perpendicular to the column, flat, emarginate at the front with a notch and denticulate at the raised back; anther cap light yellow, galeate, 1.2 × 1.5 mm, with 2 filiform lateral setae, ca. 1.5 mm long; pollinarium 1.2 mm long, with 2 globose pollinia, stipe oblong, viscidium rectangular. Fruit not seen.

Other Specimens studied: S. LOC.A cutting from holotype (K.P.Wojtas KPW230115-1), flowered in cultivation in Germany, May 2023, K.P.Wojtas KPW230521-3 (JE00028816) (JE!- paratype of C. shanica , specimen preserved in spirit). MYANMAR. Moulmein, C.S.P.Parish 55 / Reichenbach Herb. Orchid. 26237 (W0017162, https://w.jacq.org/ W0017162) (W!- holotype of Chiloschista parishii Seidenf. ); icon, Reichenbach Herb. Orchid. 11583 (W0017165, https://w.jacq.org/W0017165) (W!-isotype of C. parishii ); without locality, comm. & imp. Veitch s.n. / Reichenbach Herb. Orchid. 41550 (W0017163, https://w.jacq.org/W0017163) (W!- holotype of Thrixspermum luniferum Rchb. f. ); Reichenbach Herb. Orchid 41549 (W0017164, https://w.jacq.org/W0017164) (W!-left hand sketch, isotype of T. luniferum ). THAILAND. Mae Hong Son Province, X.Rodriguez s.n. (LY0010021, https://herbier2014.univ-lyon1. fr/fiche/7054) (LY!- holotype of C. rodriguezii ).

Flowering phenology: According to Tun (2014) it flowers in April, (shortly before start of summer).

Etymology: Named in reference to Shan State of Myanmar from where the species was reported by Tun (2014) for the first time and is still believed to be endemic to.

Distribution: Myanmar (Taunggyi District, Shan State).

Habitat and ecology: We have no information in these regards.

Conservation status: The new species, Chiloschista shanica is described from cultivated plants originating from Thailand. A photograph of this species appears as unidentified from Taunggyi District, Shan State of Myanmar in Tun (2014: p. 97). Nothing is known about the occurrence of this species currently in Thailand and the current status is not known in Myanmar either. There is no information on the habitat and ecology of this species either. In these circumstances, the species should be best assessed as Data Deficient following IUCN Standards and Petitions Committee (2022).

Figures

FIGURE 1. Chiloschista shanica K.P.Wojtas, C.Bandara & Kumar. A. Plant, B. Inflorescence (close up), C. Flower (side view), D. Petal and sepals. Photographs by Philip Wojtas.

FIGURE 2. Chiloschista shanica K.P.Wojtas, C.Bandara & Kumar. A. Flower (petal and one lateral sepal removed) (side view), B. Labellum (petals and sepals removed), C. Labellum (side view), D. Labellum (dorsal view), E. Labellum (ventral view), F. Labellum (longitudinally cut into half), G. Saccate base of labellum (longitudinal section), H. Column with foot, I. Column showing stigma and rostellum, J. Column, ovary and pedicel (side view), K. Pollinarium with anther cap (dorsal view), L. Pollinarium with anther cap (ventral view), M. Anther cap (ventral view), N. Pollinarium. Photographs by K. Philip Wojtas.

FIGURE 3. Chiloschista shanica K.P.Wojtas, C.Bandara & Kumar. A. Plant, B. Flower, (front view), C. Flower (side view), D. Dorsal sepal, E. Petal, F. Lateral sepal, G. Lip (front view), H. Lip (split into half, interior lateral view), I. Labellum dorsal view, J. Column showing stigma and rostellum, K. Column (side view), L. Column, ovary, and pedicel (side view), M. Anther cap (ventral view), N. Pollinarium. Illustration by Champika Bandara.

FIGURE 4. Chiloschista rodriguezii Cavestro & Ormerod (pictures of a cultivated plant in Thailand, originating from province Mae Hong Song). A. Plant, B. Flower (front view), C. Flower (side view), D. Flower showing labellum and column, E. Labellum (front view close up). Close ups were generated using focus stacking. Photographs by Kurt Keller.

FIGURE 5. Type drawing of Thrixspermum luniferum Rchb.f. (Chiloschista lunifera) by Rchb.f. (W!-W0017164, left hand drawing). © JACQ consortium (2004 ff.) Virtual Herbaria Website at https://www.jacq.org/ consulted on 2023-01-25. CC-BY 4.0.

FIGURE 6. Chiloschista lunifera (Rhb.f.) J.J.Sm. (pictures of a plant of unknown origin cultivated in the USA). A. Inflorescence, B. Flower (side view), C. Flower (close up of front view). Photographs by Ron Parsons.