Ardisia whitmorei Julius & Utteridge, sp. nov. (§Stylardisia)

Julius, Avelinah & Utteridge, Timothy M. A., 2022, Ardisia whitmorei (Primulaceae - Myrsinoideae), a new species from north east of Peninsular Malaysia, PhytoKeys 204, pp. 35-41 : 35

Ardisia whitmorei Julius & Utteridge, sp. nov. (§Stylardisia)

Fig. 1

Diagnosis.

Amongst the Peninsular Malaysian members of subgenus (§) Ardisia Stylardisia , the new species is easily recognised by the following combination characters: lateral veins brochidrodromous with double loops towards the margin and prominent on both surfaces, the relatively large leaves (15-23 cm long), the inflorescences with a slender rachis and branched to two orders and the glabrous corolla lobes with usually up to only two gland-dots near the apex abaxially (Fig. 1 ).

Type.

Malaysia. Peninsular Malaysia: Terengganu, Hulu Terengganu, G. Padang, trail to summit of G. Padang, 4°51.06'N, 102°53.22'E, 1236 m alt., 20 March 2010 (fl.), Mohd. Hairul et al., FRI70884 (holotype KEP!) .

Description.

A woody shrub with about 2 m high. Indumentum of scale or short, brown, simple or branched trichomes, with or without glands on vegetative and reproductive part. Leaves alternate; petiole stout, 1-2 cm long, covered with dense scale; lamina subcoriaceous, elliptic-oblong, 15-23 × 5.5-7.5 cm, base cuneate-attenuate, margin entire, apex acuminate, acumen 1-1.5 cm long, glabrous on both surfaces, except the dense, brown scale beneath; mid-rib flat above, raised below; lateral veins 21-28 pairs, closely spaced, brochidrodromous with double looping in the margin, distinct on upper surface, prominent beneath, intersecondary veins present within each pair; intercostal veins reticulate, distinct on both surfaces. Inflorescences axillary in the uppermost axils on lateral branches (see Notes), paniculate, ca. 12 cm long, 2 times branched, with flowers umbelliform at the ends of alternate branches, laxly to closely arranged on branchlets; peduncle and rachis 10 cm long, flexuous and winged, densely hairy; bracts lanceolate, ca. 1 mm long, glabrous on both surfaces, margin ciliate, deciduous. Flower 5-merous; pedicels 4-10 mm long, slender and obconically flared towards calyx base, covered with simple brown hairs, sparsely to glabrescent; calyx lobes not overlapping, spreading, covered with 2-4 brown gland-dots abaxially, glabrous on both surfaces, triangular, 1-1.2 × 1 mm, margin ciliate, with laxly spaced, pale brown hairs, apex obtuse; corolla contorted, lobes pinkish, with up to two gland-dots near apex abaxially, ovate-acuminate, ca. 3.5 × 1.5 mm, glabrous on both surfaces; stamens subsessile, anther lanceolate-mucronate, ca. 2 × 0.8 mm, glabrous, except densely covered with gland-dots near mid-rib abaxially, thecae not locellate, dehiscent by longitudinal slits; ovary globose, ca. 1 × 1 mm, glabrous, style and stigma slender, ca. 4 mm long, ovules ca. 12 in two series. Fruits with dense gland-dots, globose, ca. 4 × 4 mm, glabrous.

Distribution.

Endemic in Peninsular Malaysia, Terengganu (G. Padang).

Ecology.

Growing in primary lower montane forest.

Etymology.

The species is named after the late Dr Timothy C. Whitmore (1935-2002), a tropical botanist whose interests pertained to all aspects of tropical rain forests and who first collected this species from G. Padang.

Conservation status.

Least Concern (LC). This species is found only in one locality and G. Padang is under Taman Negara, which is a protected area. In addition, the habitat is an intact mossy forest where a healthy population was observed along the steep slopes ridge towards the summit plateau (Mohd. Hairul Mohd. Amin, pers. com.). Therefore, it is assessed as Least Concern (LC) according to the Malaysia Red List ( Chua and Saw 2006) and IUCN Red List Categories and Criteria ( IUCN 2012) and guideline version 15 ( IUCN Standards and Petitions Committee 2022).

Additional specimen examined.

Malaysia. Peninsular Malaysia: Terengganu, Gunong [Gunung] Padang Expedition, Summit plateau G. Padang, closed 40 ft. [14 m alt.] lower montane type forest on eastern side of plateau [4°51'N, 102°52'E], 4200 ft. [1280 m alt.], 20 Sept 1969 (fr.), T. C. Whitmore, FRI 12727 (KEP!).

Notes.

This species was initially flagged as distinct by Stone who assumed it to be similar to Ardisia sessilis Scheff., no doubt due to the leaf size and the venation, but to date, there is no valid name for this taxon. Although the new species shows some similarity to A. sessilis in the shape of the leaves (elliptic-oblong), which are in the same size range (15-25 cm long) and in the reticulation (intercostal veins ± reticulate), it differs from the latter in several morphological characteristics, such as the marginal veins absent (but double marginal veins present in A. sessilis ), the inflorescence rachis is slender (vs. stout) and the pedicel is longer and slender (vs. short or almost sessile and thick).

There are several members of § Ardisia Stylardisia that have large leaves and slender inflorescences rachis, but the new species most resembles Ardisia nurii Furtado in having elliptic-oblong leaves and a brochidrodromous venation. However, the inflorescence in A. nurii is usually branched to three and rarely two orders, whereas in A. whitmorei , it is branched to two orders. In addition, the brochidrodromous venation is double looped in A. whitmorei , but not in A. nurii . The new species is also similar to A. pterocaulis Miq. ( A. platyclada King & Gamble sensu Stone (1989)), also with the inflorescence rachis being slender, but A. whitmorei has inflorescences branched to two orders (vs. to three orders in A. pterocaulis ), has longer leaves, 15-23 cm long (compared to the shorter leaves, 9.5-13 cm long) with a flat lamina surface (vs. bullate), the brochidrodromous lateral veins (vs. meet in prominent looped intramarginal veins) and the corolla lobes are pinkish (vs. waxy white), that are abaxially covered with only two gland-dots near the apex (vs. over the entire surface).

The material of A. whitmorei currently available for study is rather poor and the inflorescences are found in axils of terminal leaves, but as these inflorescences are large, multi-flowered and paniculate, as well as the flowers having the style projecting from the bud, we are confident this species is best placed within § Ardisia Stylardisia . The material appears to be of plants that have had the terminal bud removed (they appear damaged at the apex) and we assume the inflorescences have had to appear from lower axils. Other subgenera with axillary inflorescences include § Pimelandra and § Akosmos, but the new species has none of the characters for those taxa, i.e. short axillary inflorescences or axillary and terminal inflorescences and both with no style extension prior to anthesis.

Excluding Conamomum utriculosum Ridl. (synonym: Amomum utriculosum (Ridl.) Holttum), about ten taxa are listed as endemic to G. Padang ( Ummul-Nazrah et al. 2011; with more not yet named due to incomplete material, but known to be distinct from known species). The addition of the new species described here brings the total number of endemic species for G. Padang to 11, suggesting that there are very likely more taxa that may be endemic and waiting to be described.

Figures

Figure 1. Ardisia whitmorei Julius & Utteridge, sp. nov. A flowering leafy twig B mature flower C aerial view of opened flower D flower dissected to show the stamen arrangement E anther, lateral (left) and front view (right) F petals removed to show calyx and pistil G calyx, abaxial (left) and lateral view (right) H ovary dissected to show the ovules I flower prior to anthesis, showing one flower with exerted style J infructescence K fruit L fruit, cross-section. (Illustration by Mohd Aidil Nordin A-I from Mohd. Hairul et al., FRI 70884 J-L from T. C. Whitmore, FRI 12727: scale bar for C similar to D, F similar to B and K similar to L).