Description from Flora of China
Ophiorrhiza lanceolata Forsskål, Fl. Aegypt.-Arab. 42. 1775; Pentas carnea Bentham.
Subshrubs, 30-70 cm tall; branches quadrangular, moderately to densely pilosulous to villous often becoming glabrescent with age. Leaves opposite; petiole 0.5-3 cm, pilosulous to villous; blade drying papery, oblong-lanceolate to ovate, 5-14 × 2-5.5 cm, adaxially scabrous or villous to glabrescent, abaxially densely villous or hirtellous at least along principal veins, base cuneate to obtuse, apex acute or shortly acuminate; secondary veins 8-10 pairs; stipules truncate to broadly rounded, 1.5-2 mm, villous, bristles 1-5, 1-4 mm. Inflorescence densely pilosulous to villous; peduncle 3-12 mm; branched portion congested-cymose often becoming lax, 1.5-4 × 1.5-4 cm; bracts narrowly triangular to linear, 0.5-1.5 mm. Flowers sessile or subsessile, distylous. Calyx densely hirtellous or villous; ovary portion subglobose to obovoid, ca. 1 mm; limb deeply lobed; lobes narrowly oblanceolate to elliptic or narrowly spatulate, 2-8 mm, usually unequal on an individual flower with nearly this entire size range found on some flowers, acute. Corolla pale purple to pink, red, white, or yellow, salverform, sparsely hirtellous to glabrescent outside; tube slender except rather abruptly swollen in throat in long-styled form (around stamens), 17-20 mm, densely barbate in throat; lobes elliptic or oblong-lanceolate, 3-4 mm, acute to obtuse. Capsules obovoid, 4-6 × 4-6 mm, stiffly papery to woody, with beak 1-2 mm tall; seeds 0.5-1 mm. Fl. Jul-Sep.
Cultivated plants of Pentas lanceolata are usually all long-styled and usually do not set fruit. They are variable in flower color, and new varieties and colors continue to be developed.
Cultivated in gardens in S China; sea level to 1500 m. Fujian, Guangdong [native to Africa (Democratic Republic of Congo, Ethiopia, Kenya, Rwanda, Sudan, Tanzania, Uganda); commonly cultivated worldwide].