Hydnophytum puffii Y.W.Low, Sugau & K.M.Wong

2. Hydnophytum puffii Y.W.Low, Sugau & K.M.Wong View in CoL — Fig. 3 View Fig

Hydnophytum puffii Y.W.Low, Sugau & K.M.Wong (2016) 125. — Type: KM Wong et al. WKM 2244 (holo SAN; iso L), Borneo, Sabah , Tongod , Gunung Tingkar , 26 Aug. 1992.

Tuber small, globose, to 20 cm; surface rugose, smooth, dark brown. Entrance holes lipped, to 1 mm across, and with or without occasional simple spines to 0.8 cm. Cavities small, regular, with smooth and warted surfaces. Stems 1 to few; to 50 by 0.7 cm; much branched; internodes 1.2–6 by 0.3–0.7 cm. Lamina narrowly obovate-lanceolate, ± falcate, margins ± parallel; 8.5 by 0.2 to 15 by 1.5 cm; apex rounded-acute, base tapering; midrib prominent below, veins c. 7 each side, often obscure; leathery to thin in texture; pale green in colour. Petiole 0.2–1.3 cm; stipules triangular to 0.05 cm, caducous. Inflorescence paired mounds to 0.4 cm across, and up to 0.4 cm long; bracts minute, caducous. Flowers not heterostylous. Calyx cupuliform, tube 0.6–1 mm long, glabrous on both sides; margin lobes not present. Corolla tubular, white; tube 1.5–2 mm long, outside glabrous, inside with a band of dense translucent hairs at the throat; lobes triangular, 1.5 mm long, 1 mm wide, outside surface glabrous, inside hairy at the basal-most part attached to the corolla tube; apex not uncinate. Stamens inserted at the corolla throat, basifixed; filaments subsessile; anthers 0.5 mm long, exserted. Style 2.5 mm long, densely papillate except at the basal quarter. Stigma 2-lobed, 0.5 mm long, surface densely papillate, exserted above the anthers. Fruit prolate, 6 by 4 mm, smooth, fleshy drupe, maturing reddish orange. Pyrenes fusiform, broadest slightly above middle, 3.5 mm long, 1.7 mm wide, with a semi-transparent fleshy thread at the base

Ecology & Habitat — Epiphytic in swampy forest, waterlogged Agathis forest, lowland to hill kerangas or heath forest over sedimentary rocks and forest over ultramafic geology; 10–500 m. Tuber inhabited by ants.

Distribution — Borneo (Sabah, E Kalimantan).

Conservation status — Low et al. (2016) assigned a status Vulnerable (VU) under criteria B1+2ab(iii,iv). At the time the taxon was considered to be endemic to Sabah. This is adjusted here to Near Threatened (NT) on the basis that collections from south-eastern Kalimantan raise the known extent to nearly 800 km and the former EOO from 15 000 km 2 to 93 000 km 2. Whilst now having a larger known range, its habitat remains highly threatened by logging and clearing for oil palm plantations. Other information: georeferenced collections 12, AOO 22 500 km 2 (using an auto-value cell width of 50 km), indicating 9 locations.

Additional specimens from Kalimantan. Endert 1647 (BO,L), Kalimantan, S0°00' E116°30', West Koetai, no. 4, near Bewaewa; Endert 2165 (BO, L), West Koetai,no. 9, near Antjabeng; Kostermans 13106 (BO,L), West Koetai, Mt Palimasan, near Tabang on Belajan River.

Notes — The exceptionally slender leaves of this species separate it from H. formicarum [1] with which it shares inflorescence characters. The specimens, however, are variable, some with smaller, thicker leaves (Kostermans 13106) others larger and more papery when dry (Endert 2165). Hydnophytum angustifolium (see Uncertain and Little Known Species) described by Merrill (1908) from the Philippines suggests a very similar facies to this species, but all the original type material is missing (see Uncertain and Little Known Species). In describing H. puffii, Low et al. (2016) contrasted the description of this later species in some detail.

The name perangustum had been proposed for this species, and was circulating in horticultural circles, but remains a nomen nudum. The name ‘ H. extendifolium’ has been applied to specimens at Leiden, but no publication has been traced.