Aglaia nyaruensis Pannell, 2020

Pannell, Caroline M., Schnitzler, Jan & Muellner-Riehl, Alexandra N., 2020, Two new species and a new species record of Aglaia (Meliaceae) from Indonesia, PhytoKeys 155, pp. 33-51 : 33

2. Aglaia nyaruensis Pannell sp. nov. Fig. 2

Diagnosis.

Aglaia nyaruensis resembles A. foveolata , from which it differs in its smooth leaflet lower surface, with the lateral veins and reticulation not prominent. These characters, combined with numerous pits on the leaflet upper and lower surfaces, make this species unique in the genus.

Holotype.

Indonesia. Kalimantan: Central, Nyaru Menteng Arboretum, off km 28 road to Sampit, alt. 50m, fl., 28 Jan 1995, K. Sidyasa with Ambriansyah, Arifin & Priyono 1422 (holotype BO; isotypes K, L).

Tree, 10-22 m high, bole 8 m, diameter 20 cm, outer bark smooth, greyish or greyish-brown, shallowly fissured and lenticellate, inner bark pink, brownish-green or brown and fibrous, sapwood pale yellow, heartwood white; latex white or absent. Young twigs densely covered with reddish-brown stellate hairs and scales.

Leaves 25-31(-60) cm long, 14-21(-34) cm wide; petiole 7-9 cm long, the petiole, rhachis and petiolules densely covered with reddish-brown stellate hairs. Leaflets 11-15, the laterals subopposite, lamina 5.5-11.0 cm long 2.5-4.0 cm wide, narrowly oblong or elliptical, pale brownish-green when dry, rounded to cordate at the asymmetrical base, acuminate at apex with the acute acumen narrow and to 15 mm long; lateral veins 10-15, ascending and curved upwards near the margin, anastomosing some distance from the margin and with further reticulation between this and the margin of the leaflet, with shorter lateral veins in between. Midrib prominent below, lateral veins and reticulation not raised and barely visible in dried leaflets, the midrib on the upper surface of leaflet with numerous pale brown stellate hairs and scales, the midrib on the lower surface densely covered with reddish brown stellate hairs and scales, numerous on the lower leaflet surface when young, glabrescent, becoming sparse on the mature lamina near the midrib and absent from the rest of both surfaces of the lamina, with numerous pits on both surfaces; petiolules to 3 mm long on lateral leaflets to 10 mm long on terminal leaflet.

Male inflorescence 20 cm long, 10 cm wide; peduncle 8-9 cm long, the peduncle, rachis and first branches densely covered with reddish-brown stellate hairs and scales; higher orders of inflorescence branches with numerous reddish-brown stellate hairs and scales. Male flower 2 mm long, 2 mm wide; pedicel 1 mm long, the calyx and pedicel densely covered with reddish-brown stellate hairs and scales; calyx cup-shaped, deeply divided into five rounded lobes, petals 5, 1.75 mm long, 1 mm wide, yellow, obovate; staminal tube 1.5 mm long, 1.5 mm wide, obovoid with a wide mouth 1.5 mm across, anthers 6, 0.75 mm long, 0.25 mm wide, inserted half way down the tube inside and protruding through the aperture; ovary 0.5 mm long, 0.5 mm wide, ovoid, densely covered with brown stellate hairs and scales on the outside, with two locules each containing one vestigial ovule. Female flowers not seen.

Infructescence 24 cm long, 26 cm wide, peduncle 8 cm; peduncle rachis and branches densely covered with reddish-brown stellate hairs and scales. Young fruits 2 cm long, 1.5 cm wide, ellipsoid, reddish-orange, densely covered with reddish-brown stellate hairs and scales.

Distribution.

One record each from Kalimantan, Brunei, Sabah and Sarawak.

Ecology.

Peat swamp forest, swampy forest on white sand, on ultrabasic soil or on yellow-brown sandy soil over Tertiary clays, with deep litter and abundant humus and living roots. Altitude to 400 m.

Vernacular name.

Jalongan sasak (Bejang b. Sitam).

Etymology.

The specific epithet of Aglaia nyaruensis refers to the type locality, Nyaru Menteng in Kalimantan.

Conservation (provisional).

This species is known from one locality each in Kalimantan, Brunei, Sabah and Sarawak and is therefore considered to be Vulnerable.

Additional specimens.

Malaysia. Sarawak: Sibu, Haman Forest Reserve, c. 3 m alt, fr 18 June 1958, Bejang b. Sitam 9169 (K); Sabah: Sandakan, Bt Tawai Forest Reserve, 400 m alt., young flowers 26 June 1996, S. Diwol & L. Madani SAN 135187 (K). Brunei, Belait: Sungai Liang, Andalau Forest Reserve Compartment 5, 4°38'41"N, 114°30'20"E, 30 m alt., sterile, 8 March 2004, A.N. Muellner, C.M. Pannell, G. Challen, Jangurun, Muhd Yussof, Ibrahim ANM2039 (K).

Figures

Figure 2. Aglaia nyaruensis Pannell A habit with male inflorescence B detail of upper leaflet surface C detail of lower leaflet showing distribution of indumentum D stellate hair E immature infructescence F male flower buds, densely covered with stellate hairs G male flower H half male flower (Drawn by Rosemary Wise, edited by Alexandra Muellner-Riehl).