Description
                                                                                                            Key Characters:
                                                                            
                                    
                                    
                                                                                                            Growth Form:
                                                                                Reclining or weakly climbing vines.                                        
                                    
                                                                        
                                                                                                                                                                                    
                                                                                                                                                                                    
                                                                                                                                                                                    
                                                                                                                                                                                    
                                                                                                                                                                                    
                                                                                                            Stems:
                                                                                Stems often swollen at the nodes, terete (cylindrical), 4–angled or –ridged, primary stems 30–60 (–100) dm long, glabrous or nearly so below, antrorsely puberulent in the inflorescence, the hairs usually reddish purple, 0.1–0.4 mm long.                                                                                
                                                                        
                                                                                                                                                                                    
                                                                                                            Roots: 
                                                                                Fibrous root system.                                                                                
                                                                        
                                                                                                            Leaves: 
                                                                                
                                                                                                                        Leaves simple.                                                                                 
                                        
                                                                                                                        Opposite.                                                                                 
                                        
                                                                                                                        Blades lanceolate to narrowly ovate or sometimes oblong–elliptic, 6.5–8.9 cm long, 1.5–2.5 cm wide.                                                                                 
                                        
                                                                                                                        Apex acute to attenuate.                                                                                 
                                        
                                                                                                                        Base leaf bases often connate around the stem, base acute to broadly obtuse.                                                                                 
                                        
                                                                                                                        Blades coriaceous, green to yellowish green, with only the midvein evident.                                                                                 
                                        
                                                                                                                        Margins slightly thickened, with a few scattered minute excrescences, each usually with a retrorsely hooked hair 0.01–0.15 mm long.                                                                                 
                                        
                                                                                                                        Midvein ± slightly excentric, usually a weakly looping vein near the margins.                                                                                 
                                        
                                                                                                                        Petioles 0.4–1 cm long.                                                                                 
                                        
                                                                                                                        Stipules absent.                                                                                                                                                            
                                                                        
                                                                                                                                                                                    
                                                                                                                                                                                    
                                                                                                            Flowers:
                                                                                                                        Flowers in inflorescence with 65–73 flowers, 10–50 cm long, internodes and pedicels yellowish green; pedicels 14–24 mm long at anthesis, elongating slightly in fruit.                                        
                                                                                Flowers bisexual (perfect), cleistogamous.
                                        
                                                                                Sepals 4.3–4.7 mm long, shallowly concave to shallowly navicular, scarcely spreading, oriented at ca. 150° to the pedicel, quickly closing.
                                        
                                                                                Corolla (petals) absent.
                                        
                                                                                Staminal filaments dimorphic, the antisepalous whorl 5.25–6.25 mm long, the alternate whorl 5.5–6.1 mm long.
                                        
                                                                                                                        
                                                                                Ovary superior, 1-celled; ovule placentation free-central; styles 5–6; stigmas receptive when flower opens.                                        
                                                                                                                                                                                                    
                                                                        
                                                                                                            Fruit:
                                                                                                                        Capsules 4.5–5 mm long; ovoid–globose.                                        
                                                                                Seeds numerous; 1–1.2 mm long; suborbicular; asymmetrical; compressed; the surface smooth; under high magnification with minute depressions; persistent on the placenta; and retained in the undehisced capsule; perisperm starchy; hard or rarely soft; true endosperm absent.                                                                                                                    
                                                                        
                                                                                                                                                                                    
                                                                                                            Ploidy:
                                                                                                                                                            
                                                                        
                                                                                                            Habitat:
                                                                                                                        Wet montane forests.
                                                                                                                    
                                                                        
                                                                                                                                                                                    
                                                                                                            Elevation Range:
                                                                                                                        1000–1220 m.