Sonerila metallica

Lin, Che-Wei, Chen, Chien-Fan, T. - Y & Yang, Aleck, 2015, Two new taxa of Melastomataceae Trib. Sonerileae: Phyllagathis rajah and Sonerila metallica from Batang Ai, Sarawak, Borneo, Phytotaxa 201 (2), pp. 122-130 : 127-129

2. Sonerila metallica C.-W. Lin, C.-F. Chen & T.-Y.A. Yang. sp. nov. ( Figures 4 , 5 ).

Diagnosis: Sonerila metallica resembles S. nervulosa . It differs in having leaves with 2(–4) rows of simple hairs between the main and lateral veins versus bulbous based hairs throughout the leaf surface ( Figure 5 , B & B). Moreover, the adaxial surface of S. metallica has a bluish tinge (structural coloration), which is lacking in S. nervulosa .

Type:— MALAYSIA. Borneo, Sarawak, Lubok Antu , Batang Ai District , 1°16’ N, 112°03’E, elev. 105–150 m, 5 July 2013, C. W. Lin 551 (holotype TAIF; isotype TNM) .

Herbs, erect, branched. Stems 5–13 cm long, 2.5–4 mm thick, terete, with dense appressed red hairs when young, glabrescent. Leaves opposite, extremely unequal. Larger leaves elliptic to obovate, 3.2–4.9 cm long, 1.6–2.1 cm wide, base oblique, slightly cordate, margin entire to slightly crenulate, tapering toward apex, apex obtuse, with appressed hairs or glabrous; adaxial surface jade green with bluish tinge, sparsely setose in 2(or 4) rows between main and lateral veins; abaxial surface pale green, glabrous, chartaceous; nerves 3 or 5, abaxial midrib and lateral veins prominent, with dense appressed red hairs; distance ratio of lateral vein to the leaf margin on both concave side and convex side ( Hickey 1973) is 1/1.2. Smaller leaves suborbicular to obovate-lanceolate, 1.5–3.5 mm long, 1–1.9 mm wide, adaxially glabrous, sometimes sparsely hairy on margins, abaxially with appressed hairs on veins. Petiole terete, 2.5–6 mm long, with densely appressed red hairs. Bracts acicular to linear, rarely oblanceolate, 1.5–5 mm long, apex apiculate, abaxially with appressed hairs on veins. Inflorescence an axillary cyme, flowers 3 or 4, with densely appressed red hairs; peduncle 0.5–2 mm long. Pedicel 3 mm long, setose. Hypanthium campanulate, 2.5–3 mm long, densely red setose. Sepals 3, triangular. Petals 3, white or pink, ovate-lanceolate, asymmetric to slightly asymmetric, 5–5.5 mm long, 2 mm wide, adaxially glabrous, abaxially sparsely setose, hairs red. Stamens 3; filaments linear; anthers oblong, obtuse, cream, shorter than filaments, ca. 2.5 mm × 1 mm. Styles filiform, ca. 7 mm long; stigma capitate. Pollen grains heterocolpate, subprolate; 20.9±1.8 × 24.9±2 μm (measured by LM); exine ca. 1 μm thick, ornamentation striate. ( Figure 5. K–O ). Fruit a capsule, campanulate, 3–3.5 × 3.5–4 mm, densely hispid-setose. Seeds 0.3–0.5 mm long, obovate in lateral view, rounded-triangular in ventral view, ventrally slightly curved, beak-like, dorsally with dense minute papillae or somewhat tuberculate, with 1–3 papillae at apex of tubercles.

Distribution and ecology:—Known only from Batang Ai Dist., Sarawak, Borneo (Figure 1); in humid, heavily shaded valleys in dipterocarp forests; 105– 150 m.

Vernacular name:—Metallic Sonerila .

Etymology:—The epithet derives from the metallic blue sheen of the adaxial leaf surface. The vernacular name refers to the texture of the leaf blades and the bluish color.

Notes:—The protologue of Sonerila nervulosa (including subsp. hirsutissima Ridl. ) reports the type specimen as having been collected between 600 and 800 m in cloud forests in northeastern Sarawak ( Ridley 1946); S. metallica is endemic to southwest Sarawak between 105 and 150 m in tropical lowland rainforests.

(LM); N, O. Pollen grain, equatorial view ( LM) ( I – O from the type C.- W. Lin 551, TAIF) .

Figures

FIGURE 4. Sonerila metallica A. Habit; B,B’. Portion of larger leaf adaxial and abaxial surface, showing distance from lateral veins to margin; C,C’. Smaller leaf adaxial surface, showing leaf variation, C’’. Smaller leaf, abaxial surface; D–D’’’. Bracts, showing variation; E, E’. Flower, top and side view; F. Stamens and filaments Ventral view, F’. drosal.view, F’’. Side view; G. Style; H, H’. Petal, showing adaxial and abaxial surface; I. Cross section of ovary; J. Immature fruit, J’. Mature fruit, J’’. Fruit, top view.

FIGURE 5. Sonerila metallica A. Habit and habitat; B. Cultivated plant at anthesis; B. S. nervulosa at anthesis;C. Leaf abaxial surface; D. Leaf adaxial surface; E. Flower, top view; F. Flower, side view; G. Fruit, side view; H. Fruit, top view; I. Seed; J. Seed, showing papillae and tubercles on dorsal surface; K. Pollen grain, equatorial view (SEM); L. Pollen grain, polar view (SEM); M. Pollen grain, polar view