Ardisia recurvisepala Julius & Utteridge, 2021

Julius, Avelinah & Utteridge, Timothy M. A., 2021, Ardisia recurvisepala (Primulaceae-Myrsinoideae), a new species from Peninsular Malaysia, Phytotaxa 480 (1), pp. 79-84 : 80-82

Ardisia recurvisepala Julius & Utteridge sp. nov. (subgenus Crispardisia) ( Fig. 1 )

Similar to Ardisia villosa Roxburgh (1824: 274) in being hairy throughout, but A. recurvisepala differs in the smaller stature (less than 35 cm in height vs.> 35 cm in height in A. villosa ), hairs shortly hirsute, thick and rusty in colour (rather than hairs being villous-pilose and white in colour), the leaves narrowly elliptic-oblong to narrowly oblong (vs. elliptic-lanceolate to ovate or oblanceolate), flowers usually arranged in a compound umbellate-cyme (rather than simple umbellate-cymes), and lateral (axillary) from the stem or rarely on a specialised lateral branch (not compound and terminal on specialised lateral leafy branches), flowers laxly arranged (not densely arranged and close to each other) and calyx green (not white).

Type:— MALAYSIA. Peninsular Malaysia: Perak, Bukit Larut , road to Gunung Hijau , 4°51.50’ N, 100 °47.25’ E, 920 m altitude, 15 July 2006 (fl.), Kamarul Hisham et al. FRI 52060 (holotype KEP!; isotypes SAN, SAR) .

A woody, undershrub 20–35 cm tall, usually unbranched. Indumentum of rusty, short, hairs either simple and segmented with or without glands, or stellate hairs, on young, vegetative and reproductive parts. Leaves spirally arranged; petioles slender, 5–7 mm long, densely hairy; lamina thinly chartaceous, narrowly elliptic-oblong to narrowly oblong, 14–23 × 2–4 cm, gland-dots sparse on both surfaces, young leaves pale brown, mature leaves dark green above, pale green beneath, base attenuate-decurrent, margin crenate with vascularized glands between crenatures, apex acuminatecaudate, with acumen 1–2 cm long, young leaves densely hairy on both surfaces, stellate hairs distributed near margin beneath, mature leaves glabrescent except denser on midrib beneath; midrib flat above, raised beneath; lateral veins obscure above, indistinct beneath, 10–19 pairs; intercostal veins obscure; intramarginal veins very faint, c. 1 mm from margin. Inflorescences lateral (axillary), occasionally terminal on short, specialised lateral branch, compound umbellate-cymose; peduncle 1.5–2 cm long, densely hairy; bracts lanceolate-oblong, 1.5–3 × c. 1 mm, apex acute, densely hairy on both surfaces. Flowers 3–6 per cyme; pedicels 1.3–2 cm long, densely hairy; calyx lobes 5, green, with conspicuous black lineate dots throughout, oblong-lanceolate, c. 2 × 1 mm, apex acute-obtuse, recurving outward, margin ciliate, densely hairy on both surfaces; corolla lobes 5, dark red, with sparsely black lineate dots throughout the surface, ovate with prolonged apex, c. 8 × 2.5 mm, apex slightly twisted and recurve apically, glabrous; stamens 5, connivent, filaments ±sessile, anthers ovate-lanceolate, c. 4 × 1 mm, connective obtuse, thecae opening with longitudinal slits, without lineate dots, glabrous; ovary ovoid, c. 1.5 × 1 mm, style and stigma filiform, c. 7.5 mm long, densely hairy, with simple hairs from the middle of ovary towards basal part of style. Fruits red, globose, 6–7 × 5–6 mm, densely hairy; ovules c. 5 in 1 series.

Phenology:— Flowers collected in July, and fruits in October.

Habitat:— Grows in an undisturbed habitat, on a slope down the forest hill away from the main road towards Gunung Hijau, Bukit Larut.

Etymology:— The species epithet is derived from the calyx shape.

Conservation status:— Vulnerable (VU). With only two collections from a single location, it is impossible to calculate a polygon for estimating the Extent of Occurrence (EOO), but using the standard 2 km 2 cell size for Area of Occupancy (AOO; IUCN 2012, 2016), Ardisia recurvisepala can be assessed as Vulnerable (VU) based on Category D ‘Very small or restricted population’, having an AOO of <20 km 2 and less than five locations. The habitat where the species was found is undisturbed and in spite of low population density, the species was still found in the same locality in 2014 from where it was first collected in 2006. Further collections and observations of the species are needed for a full assessment, including the number of mature individuals in the population.

Additional specimen examined:— MALAYSIA. Peninsular Malaysia: Perak, Bukit Larut, roadside to top of Bukit Larut , at KM 8 – KM 9 [4°52.03’ N; 100°47.11’ E], on slope, slightly under canopy, 947 m altitude, 30 October 2014 (fr.), Ummul Nazrah et al. FRI 81626 ( KEP!)

Discussion:— Ardisia recurvisepala is an endemic and rare woody shrublet and is known only from two collections from Bukit Larut, Perak ( Figure 2). This newly described species is morphologically similar to A. villosa in regard to the hairs present throughout the plant and the elongated calyx lobes, but A. recurvisepala differs from the latter in several aspects, especially the indumentum type and inflorescence structure as detailed in the diagnostic statement above.

Members of subgenus Crispardisia show different sizes and shapes of vascularized glands or bacterial nodules along crenatures of the leaf margin. The swollen parts are visible either at tips of crenature, on the upper or lower leaf surface, but in the new species described here they are ellipsoid and tiny vascularized glands, not as obvious as in the widespread species Ardisia crenata Sims (1817 : t. 1950). Microscopic observations using dried herbarium specimens shows small openings at the apex of vascularized glands which split later along the abaxial surface; rusty, short and simple, non-glandular hairs were observed inside the cavity as shown in Figure 1 (O I).

In Peninsular Malaysia, there are now nine species of the subgenus, and a key to the taxa is provided below in advance of a full revision of the subgenus for the Flora of Peninsular Malaysia account.

Figures

FIGURE 1. Ardisia recurvisepala Julius & Utteridge. A Habit, flowering. B Habit, fruiting. C Flower, bud. D Flower, mature. E Calyxlobes, showing the adaxial and abaxial surface.F Corolla-lobe, dissected.G Flower dissected to show the stamen arrangement. H Stamens, showing abaxial surface. I Anther. J Ovary and pistil. K Ovary dissected to show the ovules. L Simple, short and segmented hairs on ovary. M Fruit. N Fruit dissected to show the seed. O Vascularized glands at leaf margin: i opened abaxial glands showing hairs inside, ii elongated shape of vascularized glands on adaxial surface. Illustration by Mohamad Aidil Nordin.