Breynia hiemalis Huan C. Wang & Feng Yang (Phyllanthaceae), of sect. Cryptogynium (Müll.Arg.) Welzen & Pruesapan in subg. Breynia, is described from Yunnan, south-west China. It is known from only a single locality in the valley of the Yuanjiang River, and usually occurs in the understory of the savanna vegetation. It is characterized by its broadly elliptic to orbicular leaf blades, shallowly plate-like calyces of the staminate flowers, ovaries with clearly erose rim and urceolate capsules. Morphological comparisons with similar species are also presented.