Sonerila anisophylla J. Wai

Wai, Jarearnsak Sae & Hu, Jer-Ming, 2023, Twelve new species of Sonerila (Sonerileae, Melastomataceae) from Thailand, Phytotaxa 620 (2), pp. 107-142 : 108-110

1. Sonerila anisophylla J. Wai & J.-M. Hu, sp. nov. ( Figures 1 , 2 ).

TYPE:— THAILAND. PENINSULAR: Trang Province, 7°12’ N, 99°56’ E, 5 April 2021, P. Tippayasri 2021–1 (holotype PSU!, isotype TAI!).

Diagnosis: Sonerila anisophylla is morphologically most similar to S. moluccana Roxburgh (1820: 182) , both with anisophyllous leaves and branched inflorescences, but differs in having larger plant sizes (20–30 cm high vs. 4–15 cm), larger leaves (15–20 × 7–10 cm vs. 4–13 × 2–6 cm), sparsely to moderately hispid leaves (vs. densely pilose), larger floral bracts (5–9 × 1.5–2 mm vs. 2–4 × 0.25–0.5 mm) and sparsely hispid capsules (trichomes ca. 1 mm long) (vs. densely papillose-pilose, the trichomes 2–3 mm long).

Perennial herbs; stems creeping to ascending, usually unbranched, stout, terete, 4–12 mm thick, fleshy, hispid; main erect stems 20–30 cm high; internodes up to 1 cm long. Leaves opposite decussate, anisomorphic, adaxially light to dark green, glossy, abaxially pale green, chartaceos when dry. Larger leaves obliquely ovate, 15–20 × 7–10 cm, 1.5–2.5 times as long as wide, adaxially moderately hispid, abaxially densely hispid along veins, apex acuminate, base obliquely cordate, margin ciliate; venation pinnate; primary vein shallowly grooved above, prominent beneath; secondary veins arising from both sides of primary vein in an alternate or sub-opposite manner, 3–4 pairs; petioles 1–9 cm long, densely hispid. Smaller leaves ovate, 0.6–1.5 × 0.6–1.2 cm, adaxially sparsely hispid, abaxially moderately hispid, apex acute or obtuse, base cordate, margin ciliate; venation basal acrodromous, usually with 3–5 main veins arising from the base; petioles 0.5–1.5 cm long, densely hispid. Inflorescences terminal or axillary, simple to branched scorpioid cymes, 10–30-flowered, with scattered minute transparent glandular trichomes (seen under magnification) on peduncles, pedicels and hypanthia; peduncles erect or slightly curved, 2.7–6 cm long, green or sometimes reddish brown, hispid; peduncular bracts leaf-like, persistent, spathulate or oblanceolate, 10–12.5 × 4–5 mm, margin ciliate, abaxially sparsely hispid; floral bracts leaf-like, persistent, oblong-lanceolate or subulate, 5–9 × 1.5–2 mm, margin ciliate. Flowers 3- merous; pedicels 2.5–4 mm long, light green, sparsely hispid. Hypanthium cup-shaped to campanulate, ca. 4 × 3 mm, light green, muricate, glandular-hispid; part of hypanthium free from ovary ca. 2 mm long. Calyx lobes 3, triangular, 1.5–2 × 1.5–2 mm, abaxially glandular-hispid. Petals short-clawed, elliptic, elliptic-oblong, or obovate, 10–10.5 × 4–5 mm, apex acuminate, white, adaxially glabrous, abaxially glandular-hispid along the midvein. Stamens 3, equal, glabrous; filaments 4–5 mm long, white; anthers straight, oblong, deeply cordate at base, 3–4 mm long, yellow, apex opening with two pores. Ovary ca. 2 mm long, 3-locular; ovary crown ca. 0.5 mm high; ovules numerous; style 11–12 mm long, white; stigma truncate, papillate. Capsule cup-shaped or turbinate, ca. 4 × 4 mm, muricate, sparsely hispid. Seeds numerous, triangular ovoid, with an enlarged lateral raphe, 0.4–0.5 mm long, ca. 0.3 mm wide, ca. 0.2 mm thick (measured through SEM), dark brown; testa cells minutely verrucose-papillose, with prominent tubercles on antiraphal side; tubercles cone-shaped or dome-shaped, usually with few minute verrucose papillae on the top.

Paratypes:— THAILAND. PENINSULAR: Trang Province, Khao Chedyod , 7° 19’ 12.71” N, 99° 54’ 24.82” E, 955 m, 29 May 2016, P. Rojchana-umpawan 298 ( PSU!, TAI!). Phatthalung Province, Khao Samphu , 7° 13’ 1.73” N, 100° 0’ 4.61” E, 648 m, 30 June 2016, P. Rojchana-umpawan s.n. ( BKF!, PSU!, TAI!) Distribution:— Thailand (Trang and Phattalung Provinces ; Fig.3 ).

Habitat :— Terrestrial plant. In shaded areas of hill evergreen forest, at elevations of 600‒1000 m.

Phenology :— Flowering and fruiting were observed from March to July.

DNA barcodes:— OP431165 ( ITS), OP480469 (accD-psal), OP503731 (trnS-trnG), OP558216 (ndhC-trnV), OP 495532 (ndhF-rpl32). All sequenced from P. Rojchana -umpawan 298.

Etymology:— The specific epithet “anisophylla” refer to unequal size of two leaves in the leaf pairs.

Vernacular name:—สาวสนมใบใหญ่ (Sao Sanom Bai Yai) ( Thailand).

Proposed IUCN conservation status:— Endangered ( EN) under criteria B 1ab (iii)+ B 2ab (iii). This species is known only from three locations, each with a limited number of plants. The known extent of occurrence ( EOO) is less than 5,000 km 2 and the known area of occupancy ( AOO) is less than 500 km 2. Habitat quality can be affected by agricultural activities since some populations are very close to the agricultural areas. Therefore, we qualify this species as EN according to IUCN Red List guidelines Version 15.1 ( IUCN Standards and Petitions Committee 2022).

Figures

FIGURE 1. Sonerila anisophylla J. Wai & J.-M. Hu. A. Habit, B. Smaller leaf showing both adaxial (left) and abaxial (right) surfaces, C. Inflorescence, D. Peduncular bracts, E. Floral bracts, F. Petal showing both adaxial (left) and abaxial (right) surfaces, G. Stamen, H. Longitudinal section of a flower showing hypanthium, stigma, style and ovary, I. Fruit showing top view (above) and side view (below). All from P. Tippayasri 2021–1 (PSU). Drawn by K. Singkam.

FIGURE 2. Photos of Sonerila anisophylla J. Wai & J.-M. Hu. A. Habit, B. Inflorescence, C. Stamen, D. Fruits, E. Seed, lateral view, F. Seed showing verrucose papillae and tubercles on antiraphal side. Photos by J. Sae Wai.

FIGURE 3. Distribution map of twelve new species of Sonerila found in Thailand.