Polyalthia pakdin I.M.Turner & Utteridge, 2016

Turner, Ian M. & Utteridge, Timothy M. A., 2016, Whither Polyalthia (Annonaceae) in Peninsular Malaysia? Synopses of Huberantha, Maasia, Monoon and Polyalthia s. s., European Journal of Taxonomy 183, pp. 1-26 : 16-19

Polyalthia pakdin I.M.Turner & Utteridge sp. nov.

Figs 1–2

urn:lsid:ipni.org:names:77153637-1

Diagnosis

With its large, multi-nerved leaves the new species has generally been confused with Polyaltha bullata King , but it lacks the villose tomentum on the twigs and the strongly auriculate to cordate leaf bases. In comparison with P. bullata , the flowers are borne on shorter pedicels (<1 versus 2 cm) with shorter sepals (3–4 versus 7 mm) and petals (to 1 cm versus up to 4 cm); and with monocarps on shorter stipes (to 6 mm versus up to 10 mm).

Etymology

We are pleased to commemorate the late Prof. Kamarudin Mat Salleh (1959–2009). A leading Malaysian student of the Annonaceae , he was widely known as ‘Pak Din’ (Uncle Din in Malay, Din being the common abbreviation of names with that ending). The epithet represents a compounding of this soubriquet. Kamarudin was native to the state of Kelantan, which is part of the range of the new species.

Type

PENINSULAR MALAYSIA: TRENGGANU, Jambu Bongkok Forest Reserve [4°50’N 103°22’E], 21 Mar. 1972, L.E. Teo & G. Pachiappan KL 3033 [T & P 433] (holo-: K).

Additional specimens examined

PENINSULAR MALAYSIA: KELANTAN, Chabang Tongkat Forest Reserve [5°49’N 102°17’E], compt 77, alt. 250’ 28 Apr. 1967, K. M. Kochummen FRI 2317 ( KEP). TRENGGANU, Dunggun, Jambu Bongkok [4°50’N 103°21’E], 12 Mar. 1961, J. Carrick s.n. ( K ×2); ibid., Sekayu, Bukit Lanjut Forest Reserve [4°58’N 102°58’E], 18 Sept. 1969, H. S. Loh FRI 13467 ( KEP); ibid., Dungun, near 36th mile, Jerangau Road [4°56’36”N 103°10’42”E], 22 Sept. 1955, J. Sinclair & Kiah bin Salleh SFN 40941 (K, KEP); ibid., Sekayu Forest Reserve [4°58’N 102°57’E], compt 43, 22 Sept. 1969, T. Suppiah FRI 11853 ( KEP); ibid., Bukit Bauk Forest Reserve, compartment 8 A [4°45’N 103°21’E], 17 June 1967, T. C. Whitmore FRI 3903 ( KEP).

Description

Shrub 1–4 m tall. Young twigs drying red-brown, rather smooth and shiny, with some irregular longitudinal ridges with rounded tops, varying from glabrous to densely pale short hairy, twigs becoming black to brown with age. Leaves chartaceous to subcoriaceous (tend to look more leathery than they are to the touch), often bullate, drying grey or grey-brown, more rarely dark brown, above, brown or greybrown below with brown venation, midrib and laterals sunken above in dry leaves, prominent beneath, more or less glabrous though sometimes with pale hairs along midrib below near base, lamina oblongoblanceolate to narrowly oblong-elliptic, 17–36 × 3.5–9 cm, apex acuminate, base obtuse, generally slightly asymmetric, lateral nerves 19–24 pairs, arching and looping within margin to form a scalloped intramarginal nerve, reticulations distinct. Petiole drying dark brown to black, 6–10 mm long, 2–4 mm in diameter, sometimes with short erect pale hairs. Inflorescences subopposite leaves, single- or fewflowered. Flowering pedicel 2–8 mm long, 1 mm diameter widening distally, drying brown with minute pale hairs [some 4-merous flowers present on KL 3033], sepals ovate c. 3–4 × 2–3 mm, outside brown, minutely bumpy with short pale hairs, inside glabrous, petals thin-textured, ovate to ovate-lanceolate 6–10 × 2.5–3 mm, drying dark brown to blackish, outside minutely bumpy with adpressed pale hairs, inside glabrous, stamens many c. 1.5 mm long, carpels many. Fruiting pedicel to 2 mm thick, sepals often persisting, monocarps to 9 or more, irregularly ellipsoidal, 8–10 × 7–9 mm, drying red-brown, surface minutely pimply with pale hairs, apiculate, stipe to 6 mm long, 1 mm diameter, pimply, pale hairy. Seeds generally two, lenticular, c. 7 × 6 × 4 mm, drying golden brown with a longitudinal groove running parallel to the flat face.

Field notes

Leaves bullate (SFN 40941), dark glossy green above, paler green beneath (SFN 40941), shiny dark green above, slightly yellowish green below (KL 3033); flowers yellowish (KL 3033), petals reddish orange (SFN 40941), petals and sepals orange (FRI 2317), stamens paler reddish orange (SFN 40941), no scent with flowers (SFN 40941); fruits green (FRI 3903), fruits green turning red (FRI 11853), fruits red (FRI 13467, SFN 40941); seeds brown (SFN 40941).

Distribution and habitat

Recorded from the eastern side of Peninsular Malaysia from Kelantan and, with most records, Trengganu ( Fig. 2 ). It occurs in lowland tropical rain forest.

Conservation status

Polyalthia pakdin sp. nov. is restricted to the lowland forests of eastern Peninsular Malaysia and currently known from seven collections from five localities (two are from the Sekayu area and two from Jambu Bongkok). The Extent of Occurrence (EOO) is 1,856 km 2 falling within the Endangered (EN) threshold of less than 5,000 km 2, and the Area of Occupancy (AOO; based on a user-defined cell width of 2 km) is 28 km 2 falling within the Endangered (EN) threshold. Whilst none of the collections is contemporary (the most recent is 1972), nearly all are from forests reserves, and, in addition, one collection is from ‘roadside forest’ (J. Sinclair & Kiah bin Salleh SFN 40941). Whilst the EOO is within the EN threshold, the presence of the species within protected areas would not place the species within this category because recent satellite imagery shows the protected areas still with relatively large areas of intact forest (using the most recent Google Earth imagery). The Sekayu collections, for example, are on the edge of the very poorly known and under-collected Taman Negara National Park and more field collections are needed in such areas to better understand the distribution of this species. Without any other information, we must assume that the species is still present in these protected areas and that the protected areas still harbour the appropriate habitat for P. pakdin sp. nov. It is difficult to demonstrate trends in the reduction of habitat etc. without modern collections, and for these reasons we assign a preliminary conservation assessment of Near Threatened (NT).

Affinities

Polyalthia bullata , the species with which P. pakdin sp. nov. was formerly confused, was included in the informal group of Polyalthia species termed the Polyalthia insignis group by Johnson & Murray (1999). They characterised the group as follows: shrubs or small trees; leaves oblique, subcordate or auriculate at base, often drying grey above, brown below; inflorescences internodal to leaf opposed or sometimes cauliflorous; petals orange or red; apex of ovary woody and persistant as a short beak on the monocarp; stigmas capitate and cohering to drop as a cap at the end of anthesis, several ovules per carpel, laterally attached in vertical row and seed not pitted but with encircling groove. While Polyalthia pakdin sp. nov. does exhibit some of these characters, it does not have auriculate or cordate leaf bases and the stigmas do not seem to cohere. In fact, P. pakdin sp. nov. also comes close to the Bornean Polyalthia polyphlebia Diels which was not included in the P. insignis group by Johnson & Murray. The leaf form of P. pakdin sp. nov. and P. polyphlebia are similar but P. polyphlebia generally has greyish corky twigs, longer pedicels (8–15 versus 2–8 mm) with the flowers larger (outer petals 13–14 mm versus 6–10 mm) and the petals fleshy rather than thin in texture; with the monocarps on longer stipes (to 25 mm versus 6 mm).

Figures

Fig. 1. Polyalthia pakdin I.M.Turner & Utteridge sp. nov. A. Leafy twig with flowers. B. Inflorescence and base of leaf (abaxial view). C. Flower. D. Magnified view of abaxial surface of outer petal. E. Calyx from below. F. Stamen. G. Carpel. H. Infructescense with immature monocarp. I. Mature monocarp. J. Seed. Scale bars: single bar = 1 mm, graduated single bar = 5 mm; double bar = 1 cm, graduated double bar = 5 cm. Drawn from Carrick s.n. (A, C–E), KL 3033 (B, F, G), SFN 40941 (H), FRI 11853 (I), FRI 13467 (J).

Fig. 2. Map showing the collecting localities of Polyalthia pakdin I.M.Turner & Utteridge sp. nov.