Melastoma kemamanense L.Neo & K.M.Wong, 2017

Neo, Louise, Wong, K. M. & Tan, Hugh T. W., 2017, Studies in Southeast Asian Melastoma (Melastomataceae), 3. A new species of Melastoma from Peninsular Malaysia, Phytotaxa 317 (4), pp. 286-291 : 287-290

Melastoma kemamanense L.Neo & K.M.Wong , sp. nov. ( Figs. 1A , 2A–C )

TYPE:— MALAYSIA. Terengganu State: Kemaman District, Sungei Banum, 22 June 1932 (with flowers and fruits), E. J. H. Corner SFN 25826 (holotype SING!, isotype K!).

This species most resembles Melastoma imbricatum in its large, broad, scabrid leaves, and compact cymes bearing hypanthia completely covered by overlapping, serrate scales, but differs in its longer hypanthium scales up to 4 mm long (those in M. imbricatum up to 1.5 mm long) which are thickly overlapping (those in M. imbricatum being neatly imbricate), larger mature fruits 9–11 mm diameter (those in M. imbricatum 6–7(–9) mm), and longer petiole scales up to 4 mm long (those in M. imbricatum up to 2 mm long).

Treelet or shrub. Twigs slightly flattened in the younger parts and terete in the older parts, covered with closely appressed, lanceolate to ovate, serrate scales. Leaves with petioles 1–3 cm long, 0.1–0.2 cm wide, covered by appressed to sub-erect, ovate scales (up to 4 mm long); blades ovate-lanceolate to elliptic, (8.5–)15–18(–23) cm long, 5–8 cm wide, the midrib and 4 secondary veins sunken above and prominently raised below, covered by a mixture of larger, lanceolate, appressed scales (1–4 mm long), some with prolonged apices, and smaller, ovate, appressed scales (up to 1 mm long) with acute apices, the upper blade surface with conspicuous rows of straight or curved short (0.5–1 mm) sequences of spicule-like crystalliferous cells, such rows distally emergent as minute hairs up to 0.2 mm long (best examined in dried material under the microscope), the lower blade surface with hairs up to 0.2 mm long on the lamina and up to 0.4 mm long on the midrib and secondary veins. Flowers few ‒ many in tightly-bunched cymes; pedicels ca. 4 mm long; bracteoles caducous, not seen; hypanthia campanulate, ca. 9 mm long, ca. 8 mm wide, completely covered by densely overlapping scales, the scales flat, narrowly triangular to ovate, ca. 1.5–4 mm long, 4–8 times longer than wide, with short-serrate margins (the serrations less than 0.1 mm deep); petals ca. 10–12 mm long, 9 mm wide; stamens anisomorphic, the long stamens with an anther 8–9 mm long, a filament ca. 7–9 mm long, these joined by a connective ca. 5 mm long and bearing a 2-lobed spur ca. 2 mm long, the short stamens with an anther 6–7 mm long, directly on a filament ca. 6 mm long, without a prolonged connective; intact ovary not seen, style ca. 13 mm long. Fruits campanulate or subglobular, ca. 10–12 mm long, 9–11 mm wide when mature, completely covered with scales of the same type as that on the hypanthium; seeds not seen, noted as ‘orange in purple placenta’ (in Corner s.n.).

Etymology: —This species is named after its type locality, Kemaman, in Terengganu state, Peninsular Malaysia.

Distribution and habitat: —So far only known from forested stream banks in Kemaman, Terengganu ( Fig. 3 ). The lowland forest in this region is underlain with undifferentiated acid intrusive rocks ( Tate et al. 2008).

Vernacular name: — Sedudok ayer (notes in Corner SFN 25826, K), although all species in the genus are typically referred to as Sendudok in the Malay language.

Additional specimen examined: — MALAYSIA. Terengganu: Kemaman, Sungei Nipa, Jeram Gakah, 21 November 1935 (with fruits), Corner s.n. (K!, KEP!, SING!).

Conservation status: —Given that this species is only known from two very proximate collections and more recent documentation has not been made, we assign Melastoma kemamanense a provisional conservation status of Data Deficient (DD) following the approach of Bachman et al. (2011).

Discussion: —The differences in leaf blade shape, petiole scale form, hypanthium scale form, and fruit size which clearly differentiate Melastoma kemamanense from M. imbricatum are illustrated in Figs. 1 and 2 . The evident disjunctions in morphology, particularly in the characters which have been identified as most important for distinguishing Melastoma species, provide sufficient support that the specimens listed in this account represent a new species.

Figures

FIGURE 1. Distal branch portions, leaves (upper and lower leaf blade surfaces both presented), and inflorescences of A. Melastoma kemamanense (Corner SFN 25826, SING), B. Melastoma imbricatum (Wray 2980, SING). Scale bars: 2 cm. Photographs by L. Neo.

FIGURE 2. Scale types compared between Melastoma kemamanense and Melastoma imbricatum. A, B, C. M. kemamanense. A. Densely overlapping scales 1.5–4 mm long on the flowering hypanthium (Corner SFN 25826, SING). B. Densely overlapping scales 1.5–4 mm long on the fruit (Corner SFN 25826, SING). C. Scales up to 4 mm long on the distal end of the petiole and which are appressed on the abaxial surface and suberect on the margins (Corner s.n., SING). D, E, F. M. imbricatum. D. Imbricate scales up to 1.5 mm long on the flowering hypanthium (Curtis s.n., SING). E. Imbricate scales up to 1.5 mm long on the fruit (Goodenough 959, SING). F. Scales up to 2 mm long on the distal end of the petiole and which are mostly appressed on the abaxial surface and on the margins (Hamid 11009, SING). All scale bars: 5 mm.All photographs by L. Neo.

FIGURE 3. Distribution of Melastoma kemamanense (●) in Kemaman, Terengganu.The inset map depicts Peninsular Malaysia. The blue line denotes Sungei Nipa and Sungei Banum, streams that join the Kemaman River, which flows into the South China Sea.