Vatica mizaniana Chua 2015, sp. nov.

Type:— MALAYSIA. Terengganu: Jerangau Forest Reserve, Compartment 31, sea level, 4°55’N, 103°06’E, 21 July 2009 (fr.), S. Damahuri FRI 46949 (holotype KEP!; isotypes SAN!, SAR!).

Vatica mizaniana differs from other Vatica species by the dark purplish-black young twigs and the stipules, buds and shoots, which are almost black when fresh. Its fruit lobes are ovate, slightly woody and the nut is smooth and ovoid with three distinct sutures.

Shrub or small tree to 10 m tall, 12.2 cm dbh, occasionally with small, unbranched stilt roots. Bark smooth to sparsely lenticellate, grayish-green to grayish-brown with light grey patches, inner bark brown, fibrous and without resin, sapwood creamy-yellow, also without resin. Crown lax, branching as low as 1.5 m from base of tree, branches drooping with twigs and leaves spreading horizontally. Twigs when young densely covered with dark purplish-black stellate hairs (including stipules, petiole and young leaves), to 6 mm diameter, glabrous, older twigs not purplish black, stipules linear, caducous. Leaves leathery, glossy dark green above, pale green below when fresh, petiole 15 − 30 mm long, 2 − 4 mm thick, rugose when dried, glabrous, blade oblong-elliptic, thickly coriaceous, 27 − 42 × 6.3 − 11.5 cm, base obtuse to almost rounded, apex with a short sharp acumen 3 − 7 mm long, margin inrolled, 2 distinct rows of intramarginal veins, domatia prominent near margin, midrib very stout below, raised above, secondary veins 17 − 19 pairs, raised on both surfaces, upper surface glabrous, undersurface on midrib, lateral veins and blade sparsely but evenly covered with stellate, appressed brown hairs becoming glabrescent. Inflorescence panicle to 2 cm long, axillary and along leafless parts of twig, single branching, branchlets with up to 3 flowers, rachis pubescent purplish-brown stellate hairs, peduncle 3 mm, buds pale yellow with purplish tinge at the apex, 9 × 1 mm. Flower sepals 5, equal, lanceolate, apex acute, 2 × 1 mm long, margin inrolled, purplish-red, pedicel and sepals light grayish-brown or whitishgreen sericeous with dark brown stellate hairs, petals 4, elliptic-lanceolate, pale yellow with purplish-pink hue or white or red when fresh, purplish-brown when dried, glabrescent with appressed brown stellate hairs, 9 × 1 mm, fragrant, stamens 15 in 2 whorls, single, 1 mm long, filament less than half the length of anther, deltoid to broadly deltoid with anther attached to the apex, anther oblong, apex acute, ovary more or less broadly conical, semi-inferior, densely pubescent, style columnar, 1 mm long, stout, glabrous, slightly expanded at the apex into a conical stigma, stigmatic surface bullate, stigma more or less half the length of style. Fruit stalk to 5 mm, lobes 5, equal, free, ovate, apex acute, reflexed, upcurved distally, glabrous, slightly woody, 10 × 6 mm; nut ovoid with a pointed apex and 3 distinct sutures, 2.5 × 3.0 cm, smooth, greenish-chocolate. Germination epigeal.

Etymology:—The species is named after His Royal Highness Sultan of Terengganu Sultan Mizan Zainal Abidin ibni Al-Marhum Sultan Mahmud Al-Muktafi Billah Shah.

Distribution and habitat:—It is endemic to Peninsular Malaysia, known from Jerangau and Hulu Terengganu Forest Reserves and Sg. Pelong in the state of Terengganu. It occurs in undulating and swampy areas of a lowland dipterocarp forest on clay sandy and alluvial soils at about 90 m elev. It is present in fragmented primary and loggedover forests.

Ecology and phenology:—At least 190 trees of various sizes have been recorded in Compartment 31, Jerangau FR (Figure 4). The largest dbh recorded in this population is 12.2 cm. Because of its small stature, it is a species of the understory and is clearly differentiated from other species by its characteristic smooth Vatica bark and large leaves. On the specimen Suppiah FRI 11852 it was noted that in Sekayu it flowered when only 1.2 m tall. Species that are dominant in the Jerangau habitat include Dryobalanops aromatica Gäertner (1805: 49) (Dipterocarpaceae) on higher ground and the palms Licuala bayana Saw and Johannesteijsmannia altifrons (Rchb.f. & Zoll.) H.E.Moore (Arecaceae) in the lower swamp area. Saplings KBG 20090206 are currently being maintained in the nursery at Kepong Botanic Gardens, FRIM.

Conservation status:—Rare as defined in Chua (2012). The population in Jerangau FR Compartment 31 is currently protected in a 63-ha High Conservation Value Forest (HCVF), an approach used in forest certification schemes to ensure that areas in a natural forest that contain environmental, biodiversity and social values are appropriately managed for conservation. Identification of the local values and locations of the population are the first essential steps towards managing these values effectively. This HCVF was created in 2008 to protect a critically threatened species Dipterocarpus sarawakensis (Dipterocarpaceae) in this region. Several other dipterocarp species that have a threatened status in Malaysia such as Vatica havilandii Brandis (1895: 133), V. cf. venulosa, D. eurynchus Miquel (1861: 485), D. lowii Hooker (1860: 160) and D. verrucosus Foxw. ex Slooten (1927: 293) are also conserved here.

Notes:—The dark purplish black twig is rare among Peninsular Malaysian Vatica species. This feature is however common in the Vatica species of northwest Borneo (Ashton, pers. comm.), which forms part of the Riau Pocket that extends from east Malaya, east Sumatra to west Borneo (Corner 1978). Preliminary species inventory in the Jerangau forest indicates some floristic similarity with northwest Borneo. The Jerangau forest is possibly a remnant of the vast swamp forests that once covered the Riau Pocket.

Additional specimens examined:— MALAYSIA. Terengganu: Jerangau Forest Reserve, Compartment 31, 80 m elev., 4 o 55’N, 103 o 46’E, 22 March 2005, Mustafa FRI 46721 (KEP); Jerangau Forest Reserve, 4 o 55’N, 103 o 05’E, 4 August 2009, Chan FRI 46970 (KEP); Jerangau Forest Reserve, 88 m elev., 4 o 55’N, 103 o 05’E, 4 August 2009, Chan FRI 46971 (KEP); Sekayu Forest Reserve, Compartment 43, 22 September 1969, Suppiah FRI 11852 (KEP); Sg. Pelong, 9 April 1971, Suppiah FRI 14868 (KEP); Jerangau Forest Reserve, 4 o 55’N, 103 o 05’E, 21 April 2010, Yong FRI 65928 (KEP).