心叶山香圆 xin ye shan xiang yuan

Small trees, 2-5 m tall. Twigs robust, black-gray or brown-gray, nodes swollen, lenticels conspicuous. Leaves simple, rarely trifoliolate, opposite, sessile or shortly petiolate, no more than 5 mm; blade ovate to oblong-ovate, 11-14(-16.5) × 5.5-7(-8) cm, coriaceous, glabrous, adaxially lustrous green, abaxially pale green, main vein impressed adaxially and prominent abaxially, lateral veins 5-9(-11) pairs, slightly discernible adaxially and conspicuous abaxially, base subcordate, rarely rounded, margin glandular crenate or -serrate, apex apiculate, cusp 5-10(-15) mm. Inflorescence terminal or axillary, paniculate, ca. 11 cm, rarely cymose; pedicels dark purple, slightly pubescent, with flowers loosely arranged. Flower small, ca. 3 mm in diam., creamy with purple. Sepals yellowish white, oblong, ca. 1.5 × 1.1 cm, margin ciliate, exterior pubescent. Petals oval, ca. 2 × 1.8 mm, ciliate, inserted on disk margin. Floral disk undulate. Ovary superior; styles 3, free, as long as anther. Fruit not seen. Fl. Apr-Jun.

● Dry forests, limestone forests, wooded limestone mountaintops; ca. 1700 m. SE Yunnan (Xichou).

This species usually possesses simple leaves, whereas trifoliolate leaves are also recorded. This species has been hypothesized to be a possible transitional taxon between trifoliolate species and ones with simple leaves in this genus. Phylogenetic studies are needed to test this hypothesis.