19. Capparis wui B. S. Sun, Acta Phytotax. Sin. 9: 109. 1964.
元江山柑 yuan jiang shan gan
Shrubs or climbers, 2-4 m tall. Branches almost terete, with recurved and hooked 1-2-mm stipular spines; new twigs slender, flat, with grooves, densely rust-colored appressed shortly pubescent but glabrescent, stipular spines absent. Petiole 1-3 mm, slightly stout, trichomes like those on branches; leaf blade elliptic to almost oblong-elliptic, (2.5-)3-7.5 × (1.5-)2-4 cm, when young smaller, thin, and with dense short pubescence on both surfaces, when mature larger, thinly leathery, abaxially with persistent trichomes, and adaxially with sparse trichomes except on midvein, midvein abaxially raised and adaxially flat or impressed, secondary veins 5-7 on each side of midvein, slender, abaxially raised, and adaxially indistinct, reticulate veins not obvious on both sides, base slightly cordate, apex acute, almost rounded, or rarely emarginate. Flowers axillary and solitary or 2-4 in a corymb at twig apices. Pedicel 1.5-2.5 cm, shortly and densely rust-colored appressed pubescent. Sepals 8-9 mm, caducous shortly after anthesis; sepals of outer whorl concave to navicular, herbaceous, outside shortly pubescent, inside glabrous; sepals of inner whorl almost obovate, flat, nearly membranous, pubescent only on basal margin. Petals white, oblong-ovate, 1-1.2 cm, nearly equal, from base to middle thick and densely white tomentose, from middle to apex membranous, transparent, and glabrous, apex rounded. Stamens 38-41; filaments ca. 3 cm; anthers length unknown. Gynophore 3-4 cm; ovary ellipsoid, ca. 3 × 1.5 mm, 1-loculed; placentae 4; ovules many. Fruit gray, ellipsoid, ca. 3 × 1.8 cm, scabrous, apex shortly beaked; stipe 2-3 mm in diam., woody. Mature seeds not seen. Fl. Mar, fr. Aug-Sep.
● Dry hot valleys, thickets; 500-600 m. Yunnan (Yuanjiang).
The flowers are noted as fragrant. Jacobs (Blumea 12: 541. 1965) did not see the type but thought the species was close to Capparis siamensis Kurz of Cambodia and Thailand. However, C. siamensis differs from C. wui in having an ovate leaf blade, solitary axillary flowers, longer petals, and a tomentose gynophore and ovary. Also, C. siamensis has fruit with distinctive rows of small protuberances (see Chayamarit, Fl. Thailand 5(3): 256. 1991), but, unfortunately, fruit of C. wui have never been collected.