Castanopsis corallocarpus W.H.Tan & Strijk, 2023

Tan, Wei Harn, Ong, Lisa & Strijk, Joeri Sergej, 2023, Castanopsis corallocarpus (Fagaceae), a new species from Royal Belum (Perak) in Peninsular Malaysia, PhytoKeys 219, pp. 1-10 : 1

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scientific name

Castanopsis corallocarpus W.H.Tan & Strijk

sp. nov.

Castanopsis corallocarpus W.H.Tan & Strijk sp. nov.

Figs 1 View Figure 1 , 2 View Figure 2

Type material.

Holotype. Malaysia, Sungai Tiang, Royal Belum State Park, Hulu Perak District, Perak State, elevation 417 m, 11 January 2022, W.H. Tan TWH002, Holotype: KEP; Isotypes: IBER [IBER00000000030; IBER00000000031]. Paratype. Malaysia, Sungai Papan, Royal Belum State Park, Hulu Perak District, Perak State, elevation 290 m, W.H. Tan TWH003, Paratype: KEP; IBER [IBER00000000032, IBER00000000033]. Due to the small number of individuals and precarious conservation status, detailed locality information is not released here, but can be requested from the authors.


Castanopsis corallocarpus is a medium-sized tree. It differs from similar species by its fruits which carry unique rows of basally reinforced, blunt coral-like spines on the cupule exterior, combined with singular rounded rectangular nuts which are slightly asymmetric. Currently, the species has been found in two localities, both in Royal Belum State Park and each consisting of one individual. Several additional individuals resembling C. corallocarpus were reported by our field staff in Temenggor Forest Reserve, Perak, but this is awaiting confirmation. Pending further discoveries, the species appears to be locally restricted to low-mid elevation forests of the BTFC.


Medium size tree, approximately 16-20 m tall, no buttresses. Bark lenticellate grey. Sapwood reddish-brown to pink. Branches glabrous, densely lenticellate, dark-brown to grey-white. Leaves simple, thin-coriaceous, papery when dried, lamina elliptic, up to (11)13-17(19) × (2)3.5-5(6) cm. Leaf apex acuminate; base cuneate, occasionally somewhat asymmetric. Margin entire. Both surfaces glabrous. Leaves dark green above and glaucous below. New shoots exhibit flushing. Venation pinnately veined, secondary venation eucamptodromous. Pairs of secondary veins 9-10(11), raised on underside of leaf. Tertiary veins scalariform, but scarcely visible on underside. Male and female inflorescences not seen. Peduncles 7-11 cm long, up to 0.4 cm in diam. at the base, glabrescent, grey-brown and densely lenticellate. Infructescence a woody spike, terminal, ranging from 9-10 cm. Fruits sessile on woody peduncle, spread out on spike and not clumped. Very few fruits make it to maturity, with typically 1-3 units fully ripening. Acorn globose or ovoid when developing, globose when mature, 3.3-3.8 × 2.7-3.3 cm, covered with 4-5 eccentric ridges with blunt thick coral-like spines, originating from the style scar looping towards the suture that runs along the spine of the fruit, surface puberulous. Cupule fully enclosing the nut, mostly indehiscent, but occasionally dehiscent, exposing exocarp area. Fresh cupule wall bright green, suture dark grey-black. Old cupule grey-green, darker on the surface lighter on the spines. Nut 1 in each cupule, oblong in shape, flat at the bottom, 2.5-2.9 × 2.3-2.4 cm, tip pointing down. Up to 90% of the surface area of the nut comprising scar area (receptacle tissue) and up to 10% of the surface area of the nut is slightly raised and made up of vestigial exocarp layer. Nut scar pale brown-whitish with glabrous, rugose surface, adnate to the cupule, exocarp layer light brown, covered in thin layer of silvery tomentum.


Flowering and fruiting occur annually, with flowers appearing in March and fruits maturing in July to August. Sporadic fruiting was observed in November and December 2021.

Distribution, habitat and ecology.

Castanopsis corallocarpus is only known from the Belum-Temenggor Forest Complex, Hulu Perak District, Perak, Malaysia. Within BTFC, this species has been officially recorded in Sungai Tiang and Sungai Papan as shown in Fig. 3 View Figure 3 . This species grows in both lowland and hillside dipterocarp forests (300-450 m above sea level) with a soil type of low nutrient and high clay abundance typical of most dipterocarp forest. As Peninsular Malaysia is situated near the Equator, the climate is classified as wet equatorial, characterised by high daytime temperature and high rainfall throughout the year. According to The Malaysian Meteorological Department (2022), the District of Hulu Perak experiences an average rainfall of 1500-2000 mm annually and the daytime temperature is around 27-30 °C and 21-24 °C at night with very minimal fluctuations seasonally.

Vernacular name.

Both indigenous communities of BTFC (i.e. the Jahai and Temiar) do not have a specific name in their language, instead referring to it in Malay as Berangan.


The epithet corallocarpus, a noun in apposition, alludes to thick coral-like spikes arranged in undulating thickened ridges on cupule of fruit.

Conservation status.

Based on the guidelines established by the IUCN Red List ( IUCN 2022), we provide an initial assessment of the species here as Critically Endangered (CR B1B2ab(i,ii,iii,iv)), based on only two recorded individuals within Royal Belum State Park, small known range (BTFC) and the extensive habitat alteration and forest clearance throughout the immediately adjacent wider region. Although Royal Belum State Park is fully protected from logging, the southern part of BTFC namely Temenggor Forest Reserve is open to exploitation, further threatening to shrink its already small range.