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| Driessenia phasmolacuna C.W. Lin
in Lin, 2019.
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Abstract
A new species, Driessenia phasmolacuna C.W. Lin, from Batang Ai, southwestern Sarawak, is described and illustrated. It belongs to a distinct group of Driessenia that have subequal or unequal leaves in each pair, often congested cymose inflorescence with many tiny flowers. Morphologically, it is similar to D. sessiliflora, but differing in its stem being 4-winged (vs. wing absent), larger laminas 18–22 × 5–7 (vs. 13–14.5 × 3.7–5) cm, much longer pedicel 3–5 (vs. 0.1–0.5) mm long, shorter bracts ca. 0.3 (vs. 1–1.5) mm long, pedicel 3–5 (vs. 0.1–0.5) mm, petal white (vs. yellowish) and ovary subequal in length to hypanthium (vs. exceeding hypanthium by one fourth) in fruit. Detailed comparison of the new species with five phenetically similar species are also presented.
Keyword: Borneo; Driessenia; Melastomataceae; New species; Sarawak; Sonerileae
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| Fig. 1. Driessenia phasmolacuna C.W. Lin. A. Habit; B, B'. Dimorphic leaves, showing extremely unequal in size and shape; C. Inflorescence on stem; D, E. Flower, face and side views; F. Longitudinal section of flower; G. Petal; H. Stamen, side view; I. Immature fruit, face view. |
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| Fig. 2. Driessenia phasmolacuna C.W. Lin. A. Habit and habitat; B. Flowering branch; C, D. Smaller leaf, abaxial and adaxial surfaces; E. Petiole; F. Portion of leaf abaxial surface; G. Inflorescences on stem; H. Inflorescence; I. Longitudinal section of flower; J. Stamen; K. Immature fruits; L. Flower, face and side views. |
Driessenia phasmolacuna C.W. Lin, sp. nov.
Diagnosis: Driessenia phasmolacuna resembles D. sessiliflora C. Hansen (1985: 340), differing in its 4- winged internodes (vs. wing absent), larger laminas 18– 22 × 5–7 (vs. 13–14.5 × 3.7–5) cm, much longer pedicel 3–5 (vs. 0.1–0.5) mm, shorter bracts ca. 0.3 (vs. 1–1.5) mm and ovary subequal in length to hypanthium (vs. exceeding hypanthium by one fourth) in fruit.
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Distribution and ecology: This new species is endemic to Sarawak, currently only known from Batang Ai (Fig. 3). It grows in lowland mixed dipterocarp forest, on semi-shaded sandstone cliffs at 100–250 m elevation.
Etymology: Named after Lubok Antu, in Malay language which means ‘Ghost Pool’, where the new species was discovered.
Che-Wei Lin. 2019. Driessenia phasmolacuna (Sonerileae, Melastomataceae), A New Species from Batang Ai, Sarawak, Borneo. Taiwania. 64(1); 69-73. DOI: 10.6165/tai.2019.64.69
