Son La Prov., Van Ho Distr., Tan Xuan comm., A Lay village, around point 20°40’46.2N 104°39’49.6E. Secondary evergreen broad-leaved forest on very steep rocky slopes composed with red-brown sandstone and shale at elevation 1300-1500 m a.s.l. Herbaceous vine 4-5 m long in open rocky place. Fruit green. Not common.