Parainvolucrella scabra

Description. Annual or perennial herbs. Stems decumbent, ca. 1 m long, roughly angular, usually rooted at nodes; branches ascending to 30 cm high. Leaves opposite, subsessile to petiolate, petiole to 3 mm long; blades 2.0 - 7.0 x 1.0 - 3.0 cm, narrowly ovate to ovate, apex acute, base cuneate; leaf scabrid adaxially and along the veins abaxially; mid-rib depressed adaxially and prominent abaxially; secondary veins 5 - 6 on each side. Stipules ca. 3.0 x 2.0 mm, triangular, fimbriate with tipped colleters, excurved, pubescent abaxially. Inflorescence terminal, (2 -) 3 - 8 (- 12) - flowered, congested-cymose, usually subtended by 4 involucral leaves; peduncle subsessile; bracts 2 - 3 mm long, narrowly ovate, scabrid; bracteoles ca. 1 mm long, truncate to broadly ovate-triangular, fimbriate with tipped colleters, glabrous. Flowers heterostylous, pedicels to 0.8 mm long. Hypanthium ca. 0.8 mm long, obconic, 4 longitudinal projections against the lobes; lobes 4, ca. 1.5 x 0.4 mm long, narrowly triangular to narrowly oblong, scabrid. Corolla white, tube 1.5 - 2.0 mm long, glabrous abaxially and pubescent adaxially; lobes 4, 2.3 - 2.8 x 0.7 - 0.8 mm, oblong. Stamens 4, anthers 0.6 - 0.7 mm long. Stigma bilobed, 0.5 - 0.6 mm long, papillate. Longistylous flowers: stamens included, filaments adnate to the base of corolla tube, filaments ca. 2 mm long; styles ca. 4.3 mm long, exserted, included part pubescent, stigma ellipsoid. Brevistylous flowers: stamens included; filaments adnate to the base of corolla tube, filaments ca. 5.6 mm long; styles ca. 2 mm long, exserted, pubescent, stigma clavate. Fruits ca. 2.1 x 2.3 mm, subglobose, with 4 longitudinal projections when young, scabrid, indehiscent. Seeds trigonous, 0.4 - 0.5 mm, numerous, black; testa reticulate.