Ardisia gasingoides Julius & Utteridge, 2017

Julius, Avelinah, Kajita, Tadashi & Utteridge, Timothy M. A., 2017, Ardisia gasingoides (Primulaceae-Myrsinoideae), a new species from southern Peninsular Malaysia, Phytotaxa 291 (4), pp. 281-286 : 282-285

Ardisia gasingoides Julius & Utteridge sp. nov. (subgenus Stylardisia ) ( Fig. 1 )

Similar to A. cockburniana C.M.Hu , A. crassa C.B.Clarke and A. crassiuscula C.M.Hu , and forming a group of Peninsular Malaysian members of Ardisia subgen. Stylardisia sharing a lack of an intramarginal vein and having relatively short and obconically flared and thickened pedicels, but A. gasingoides differs in smaller leaves less than 3.5 cm wide (rather than 3–8.5 cm wide), leaf margins sometimes distally dentate (not completely entire), shorter few-flowered inflorescences only up to 3 cm long (not many-flowered and up to 25 cm long), and especially the turbinate fruits with 5 sides displaying a pentagonal shape in cross-section (not globose to subglobose and circular in cross-section).

Type:— MALAYSIA. Peninsular Malaysia, Johor, Kuala Marong near rocky stream, 40 m a.s.l., 2º31’N ; 103º22’E, 12 September 2015, Julius et al. FRI 73518 (holotype K!, isotype KEP!) .

Slender shrub 1.3–4 m tall, stem glabrous, branches subtended by normal leaves, slender, short, slightly flexuous, glabrous except for rusty glandular hairs on young part. Indumentum of simple, short, rusty or pale brown, glandular hairs, 0.06–0.1 mm long on vegetative and inflorescence parts. Leaves alternate; petioles 4–10 mm long, winged by the decurrent leaf base, black when dry, glabrous; lamina chartaceous, with gland-dots distributed all over, conspicuously on both surfaces, lacking glandular hairs but sparsely scaly beneath, glabrous above, oblong-elliptic or occasionally oblanceolate, 6.5–12 × 2–3.5 cm, drying usually olive green, occasionally brown, base cuneate-attenuate, margin ± entire, or shallowly dentate distally, apex acute to shortly acuminate, ± caudate, acumen 8–15 mm long, glabrous on both surfaces; midrib flat above, raised beneath; lateral veins 9–12 pairs, distantly spaced, semicraspedodromus, arching and joining close to the margin, distinct on both surfaces, intersecondary veins present; intercostal veins reticulate, distinct on both surfaces. Inflorescences terminal on lateral branches or on short, side twigs of lateral branches, with up to four branches to the first order only, corymbose or subumbellate, sometimes with leaf-like bracts; peduncle and rachis 1.2 cm long, lengthening to 3 cm long in fruit, sparsely glandular hairy, slightly flexuous; bracts lanceolate, ca. 2.2 × 0.5 mm long, densely glandular hairy outside. Flowers ca. 5 per branch; pedicels stout, short, ca. 2.5 mm long (lengthening, and becoming obconically flared, to 4 mm long in fruit), black when dry; calyx lobes 5, whitish, not overlapping, spreading, covered with pale brown gland-dots, densely glandular hairy outside, narrowly lanceolate, 0.9–2 × 0.4 mm, margin ciliate, with irregularly spaced, pale brown glandular hairs, apex bluntly acute, tube ca. 0.5 mm long; corolla lobes 5, white, with scattered gland-dots, ovate-acuminate, ca. 3.2 × 0.8 mm, glabrous on both surfaces; stamens 5, filaments ca. 0.3 mm long, anthers lanceolate-mucronate, ca. 1.7 × 0.4 mm, glabrous, thecae not locellate, dehiscent by longitudinal slits; ovary oblong, ca. 1 × 0.8 mm, gland-dotted, glabrous, style and stigma stout, ca. 2.5 mm long, ovules ca. 32 in irregular series. Fruits whitish green when young, ripening red to black, with elongated-brown-dots, sparsely glandular hairy, turbinate, 6–7 × 5–7 mm, 5 sided, with raised knobbly ribs at edges imparting a pentagonal appearance in cross-section, apex truncate with pointed remnant style, and surface ridges. Seed 1, seemingly spongy, turbinate, ca. 2 mm in diameter.

Distribution:—Endemic to Johor, southern part of Peninsular Malaysia, collected from Gunung Belumut and Endau-Rompin State Park (Kuala Marong and Bertedung Camp).

Habitat:—The habitat preferences of this new species are near river banks or rocky streams in primary forest below 450 m elevation.

Phenology:—Flowers collected in September, and fruits from April to September.

Preliminary conservation status:— Ardisia gasingoides is currently known from only four locations and restricted to southern Peninsular Malaysia, with an EOO of 483 km 2 within the Endangered threshold of the IUCN categories. The species is, however, found in two protected areas, with the northerly population in the Endau-Rompin State Park and the southern one in Department of Wildlife and National Parks Peninsular Malaysia: Gunung Belumut protected area. In addition, the species has been collected recently and, during field work at the type locality in 2015, a large population was observed with many healthy seedlings growing along the pathway near a river bank. Therefore, we assign a preliminary classification of Least Concern following the IUCN Red List Criteria ( IUCN 2012, 2016). We would review this if the protected status of Endau-Rompin and Gunung Belumut were to change, but Endau-Rompin is one of the most iconic protected areas in Peninsular Malaysia and therefore the species assignment is unlikely to change status.

Etymology:—The epithet gasingoides comes from the word “gasing”, the Malay term for spinning top, and refers to the fruit shape.

Discussion:—This new species is unique in the genus Ardisia in having short, flared and thickened pedicels (especially distinct in fruit), few flowers per inflorescence and especially the turbinate, ridged and 5-angled fruits. We place A. gasingoides within subgenus Stylardisia by its shrubby habit, leaf margins without glands in the marginal sinus, inflorescence position borne on lateral branches without any specialized crowded verticillate leaves, and spreading distinct calyx lobes at anthesis (see Stone 1989). In the absence of maturing flower buds with an exserted style prior to anthesis, however, it can be confused with subgenus Acrardisia , which has a similar inflorescence position (terminal on lateral branches) with styles that are included at anthesis. The new species can be placed with a group of subgenus Stylardisia from Peninsular Malaysia that have a consistent inflorescence and floral morphology, including often the presence of a leaf-like bract in the inflorescence and the obconical flared and thickened pedicels: A. cockburniana C.M. Hu (2002: 505) , A. crassa C.B. Clarke (1882: 518) and A. crassiuscula C.M. Hu (2002: 505) . Further sampling and analysis are needed to assess whether these species form a monophyletic group and the inflorescence and floral characters are useful homologies. Hu & Vidal (2004) use the presence of scales, as found on the abaxial lamina of A. gasingoides , to key out subgen. Stylardisia . Ardisia gasingoides differs from all these species in the smaller leaf size (less than 3.5 cm wide v. 3–8.5 cm wide), leaf margins being sometimes dentate (other species having entire margins), fewer secondary veins (less than 12 pairs v. up to 25 pairs), and especially the fruit morphology (fruits turbinate with endocarp surface ridged v. subglobose to globose and with a smooth endocarp). We have updated below the key from Tree Flora of Malaya ( Stone 1989) to include the new species described here, as well as the morphologically similar taxa with flared pedicels.

As part of the ongoing revision of the genus in Peninsular Malaysia, we examined material from surrounding regions, specifically Thailand, Borneo and Sumatra, and there are no species with the distinct obconical flared pedicels in taxa of subgenus Stylardisia —all species have slender pedicels. In addition, the fruit shape is unique for the genus and no species in Peninsular Malaysia have turbinate, 5-angled fruits. The only other taxon within Malesia with similarly shaped fruits is Ardisia turbinata B.C. Stone (1990: 53) , but that species has a 12-sided fruit and is a member of subgenus Tinus (with lateral inflorescences from the main stem and markedly overlapping sepals, amongst other characters), and known only from Papua New Guinea.

Additional specimens examined (paratypes):— MALAYSIA. Peninsular Malaysia: Johor, Kluang, Gunung Belumut , Hutan Lipur Gunung Belumut , camp site, trail to waterfall, at slope of river bank, 2º04’N 103º31’E, 107 m a.s.l., 6 April 2011, Imin et al. FRI 74697 ( K!, KEP!, SING!) ; ibid., Gunung Belumut, Trail 7 during ‘ Ekspedisi Saintifik Gunung Belumut 2009’, 2º04.15’N 103º31.40’E, 90 m a.s.l., 13 August 2009, Nor Ezzawanis FRI 58384 ( SING!) ; ibid., Gunung Belumut , upper camp, banks of rocky stream, 2º02’N 103º34’E, 426 m a.s.l., 15 May 1968, Whitmore FRI 8755 ( K!, KEP!) ; ibid., Mersing, Endau-Rompin State Park, trail to Bertedung Camp from Lubuk Merekek , hill mixed dipterocarp forest, riverine, 2º27’N 103º16’E, 333 m a.s.l., 2 July 2012, Kamarul Hisham et al. FRI 67284 ( K!, KEP!) .

Figures

FIGURE 1. Ardisia gasingoides Julius & Utteridge. A Habit, flowering branch B Inflorescence, close up C Calyx D Corolla lobe, abaxial view E Corolla lobe, adaxial view F Stamen, abaxial view G Stamen, adaxial view H Placenta and ovules I Habit, fruiting branch J Leaf margin with the details of venation K Fruit, lateral view L Fruit, apical view. A–H from Julius et al. FRI 75218 (K) and I–L from Imin et al. FRI 74697 (K). Scale bars: A, I = 2 cm; B = 2.3 mm; C–E = 1.3 mm; F, G = 1 mm; H = 0.5 mm; J–L = 3 mm. Illustration by Naoko Yasue.