Tên Khoa học: Rhaphidophora lacduongensis V.D.Nguyen & B.H.QuangTên tiếng Anh: Tên tiếng Việt: Trâm đài lạc dươngTên khác:
Climbing secondary hemiepiphyte on medium height trees, juvenile plants creeping on rocks, mature stems cylindrical, reaching to 10 m, branching shoots long, many at upper part. Juvenile stem cylindrical, smooth, internodes 2.5-4 cm long, 6-10 mm diam, green, occasionally light grey, rarely with delicate and drying decayed sheath at the nodes; adult stem cylindrical, 1.5 cm diam, internodes 7-20 mm long, with leaf petiole scars obvious, falcate, to 1.2 cm long, sheath scars prominent and encircling stem, brownish. Leaf blades entire, abundant in young plants, in adult plants leaves mainly concentrated at shoot tips; petiole slender, 20-30 cm long, canaliculate, margin with sheath up reaching to pulvina, petiolar sheath soon drying black, degrade into delicate bands, deciduous; petiole base strongly pulvi- nate,1-1.5 cm wide, apex pulvinate, pulvinus 1-2.5 cm long, smooth; leaf blade oblong-ovate to ovate, 18-32 by 5-18 cm, base round, oblique, apex finely acuminate; primary lateral veins in 9-12 pairs, diverging at 40-45° to midrib, prominent; interprimary veins obvious, 1-2 cm distant from each other; smaller veins dull, 3 mm distant; secondary venation reticular. Inflorescence solitary on free flowering shoot; peduncle stout, stiff, straight, 9-10 cm long, 1.2 cm diam, dark green; spathe not seen; spadix cylindrical, 8.5-9 cm long, 1.5-1.7 cm diam, apex round to blunt, light yellow. Stamens 4; filament flat, subequal to ovary in length, 1 mm wide, anther elliptic, raised above pistil at staminate anthesis period, c. 1 mm; ovary 4 by c. 3 mm, stylar region slightly wider than ovary, hexagonal in plane view, surface deeply concave; stigma punctiform, slightly prominent from stylar region surface; ovules c. 15, attached along axil placenta, 1-1.5 mm long, stipe slender, shorter than ovule.
Distribution & Habitat
Known only from Lam Dong and Khanh Hoa Province, Vietnam. Rhaphidophora lacduongensis climbs on medium height trees of Lauraceae in evergreen montane forest at 1500-1700 m altitude.
Flowering (possibly) from March to May; fruit¬ing from May to August.
The species occurs on two sites that are less than 40 km distant, giving an extent of occurrence of less than 100 km . Both sites are very restricted areas (each less than 10 km2). In Lac Duong (Lam Dong prov.), the plant grows nearby the road from Khanh Hoa to Da Lat, and would be threatened by any road construction programme. In Hon Ba Nature Reserve (Khanh Hoa prov.), the plant is very rare (fewer than 50 mature individuals observed). It is vulnerable to anthropogenic threats such as forest fire, forest clearance, etc. According to IUCN (2012) criteria, R. lacduongensis is provisionally categorized as VU B1,2 D2 (Vulnerable).