Pilea hexagona C. J. Chen

Subshrubs small, stipules, petioles, both surfaces of leaf base, and perianth lobes of flowers densely covered with cystoliths. dioecious; Stems roundly 6-angled, ca. 20 cm tall, ca. 6 mm in diam., sparsely pubescent on grooves; internodes 1.5-4 cm. Leaves crowded at stem apex; stipules soon deciduous, green, oblong, 25-30 mm, papery, longitudinally 9-ribbed; petiole unequal in length, 4-11 cm; leaf blade abaxially pale green, adaxially dark green, elliptic, ovate or oblong, symmetric, subequal in size, 10-18 cm, succulent, but thick papery when dry, 3-veined, lateral veins 8-12 each side, elevated abaxially, base rounded or cordate, margin crenate-serrate or subundulate from middle, apex short acuminate or cuspidate. Inflorescences solitary; borne on tops of branches, male cymes dichotomously branched 2-3 times; ca. 5 cm, glomerules capitate, 6-10 mm in diam.; female inflorescence a lax corymbose cyme, 7-10 cm (including gracile peduncle 6-8 cm). Male flowers pedicellate, in bud ca. 2 mm; perianth lobes 4, cymbiform, connate about 1/2 of length; stamens 4; rudimentary ovary minute. Female flowers subsessile, ca. 1 mm; perianth lobes light blue, dorsal-ventral lobes cymbiform, longer than lateral, lateral 2 lobes oblong, subapically corniculate; staminodes dark brown, subsucculent. Achene purplish spotted. ovoid, ca. 2.8 mm, compressed. Fl. Apr-May, fr. Jun-Sep.

SE Yunnan (Hekou) [N Vietnam].

Wet rocky places in limestone mountains; ca. 200 m.

Pilea hexagona là loài thực vật có hoa trong họ Tầm ma. Loài này được C.J. Chen miêu tả khoa học đầu tiên năm 1982.

六棱茎冷水花（学名：Pilea hexagona）是荨麻科冷水花属的植物。分布于越南以及中国大陆的云南等地，生长于海拔200米的地区，一般生长在山坡半阴坡潮湿处石上，目前尚未由人工引种栽培。