Alangium gracile W.J.de Wilde & Duyfjes, 2017

de Wilde, W. J. J. O. & Duyfjes, B. E. E., 2017, The species of Alangium section Rhytidandra (Alangiaceae), Blumea 62 (1), pp. 75-83 : 78

4. Alangium gracile W.J.de Wilde & Duyfjes , sp. nov.

Resembling Alangium ferrugineum C.T.White but differing in its slender and long peduncle, 8‒40 mm long, c. 0.5 mm diam, and fruit glabrescent, 15‒20 mm long (peduncle 5‒15 mm long, 1‒1.5 mm diam, and fruit densely hairy, 30‒35 mm long in A. ferrugineum ). ― Type: Forman et al. LAE 52499 (holo L L2500089 ; iso A, BRI, CANB, K, LAE, all n.v.), Papua New Guinea, ridge SW of Efogi Village, Central Province , Port Moresby Subdistrict , S9°10' E147°39', 1370 m alt., 25 Sept. 1973, fl .

Etymology. The species epithet ‘ gracile ’ refers to its slender peduncle and corolla in bud.

Shrub or tree 3‒7(‒15) m tall; twigs (dark) brown, 1.5‒3(‒5) mm diam, ferruginous or rufous-hairy, hairs 0.2‒0.5 mm long. Leaves: petiole 0.5‒1 cm long, hairy; lamina drying reddish brown, hairy or late glabrescent, elliptic, 7‒15(‒17) by 3‒6(‒8) cm, base hardly asymmetric, cuneate, apex acute-acuminate; veins pinnate, 5‒8 at each side, tertiary venation (reticulate and) scalariform. Inflorescences hairy as the twigs, simple, 3‒10-flowered, peduncle slender, 8‒40 mm long, c. 0.5 mm diam. Flowers densely hairy,hairs rufous, 0.3‒0.5 mm long;pedicel 1‒3 mm long; corolla in bud c. 10 mm long, slender, c. 1 mm diam, base not swollen, apex subacute; ovary and calyx densely coarsely rufous-hairy, c. 2.5 mm long, constricted below the limb, not ribbed; limb 0.5‒1 mm long, spreading, with 5 low, obtuse lobes less than 0.5 mm long; petals 5, inside glabrous (or hairs extremely minute), c. 10 mm long, connate at base into a tube 1‒1.5 mm long; stamens 5, c. 10 mm long, filament c. 6 mm long, anther 3(‒4) mm long, connective glabrous; style c. 8 mm long, glabrous, stigma lobes c. 1 mm long. Fruit 1(‒3) per infructescence, ellipsoid-fusiform, 15‒20 mm long, early glabrescent, smooth or finely 5-ribbed; calyx remnant small, spreading, like calyx limb in flower, hairy or late glabrescent.

Distribution ― Papua New Guinea (Eastern Highlands and Central Provinces).

Habitat & Ecology ― Montane forest, stream side, scattered in forest; 1060‒2600 m altitude; flowering from September to December; fruiting from September to November.

Field-notes ― Fruit ochre suffused red; fruit red.

Additional specimens studied. PAPUA NEW GUINEA, Central Prov., Boridi, Carr 13273, 1525 m alt., 20 Sept.1935,fr.; Carr 14214, 1460 m alt., 27 Sept. 1935, fl.; Carr 14486, 1370 m alt., 9 Oct. 1935, fr.; Carr 14684, 1066 m alt., 22 Oct. 1935, fl.; Foreman & Vinas LAE 60189 , S9°05' E147°38', 1370 m alt., 30 Sept. 1973, fl.; Central Prov., Lala River (most likely Laila River ), Carr 14095, 1830 m alt., 30 Dec. 1935,fl.; Central Prov. ,Efogi, Croft & Vinas NGF 34867, 1400 m alt., 21 Sept. 1973, fr.; Forman et al. LAE 52499 (type), S9°10' E147°39', 1370 m alt., 25 Sept.1973, fl.; Stevens LAE 50424 , S9°10' E147°35', 1110 m alt., 5 Sept. 1970,fl., fr.; Eastern Highlands Prov., Stevens LAE 50498 , Marafunga, S6°05' E145°15', 2600 m alt., fl., fr .

Notes ― 1. Alangium gracile is vegetatively similar to A. ferrugineum , but differs in having inflorescence and flowers more coarsely hairy, peduncle more slender, and fruit smaller; ovary and calyx limb differ also considerably, not constricted below the limb in A. ferrugineum . In A. gracile ovary and limb are reminiscent of those of A. pilosum , but these are much less conspicuously hairy.

2. Like in A. ferrugineum , also in A. gracile the leaves have the lateral veins frequently tending to be 3-plinerved at base.