Vahliaceae
Mohammad Amin Siddiqi
Stewart Herbarium, Gordon College, Rawalpindi.
Annual or biennial. Stem erect, profusely branched, glabrous, pubescent or glandular-pilose. Leaves opposite, simple, entire, exstipulate. Inflorescence a sympodial cyme. Flowers axillary, usually in pairs, subsessile or pedicellate, regular, white or yellow. Sepals 5, valvate, lanceolate, densely pubescent, adnate to the ovary. Petals 5, free, imbricate, ovate or obovate-spathulate with a truncate base. Stamens 5, free, alternating with the petals, inserted on the margin of the epigynous disc. Pistil bi- or -tri¬carpellary, syncarpous, inferior; ovary unilocular; ovules numerous, attached to 2-3 thick pendulous orbicular placentas; styles 2-3, thick and divaricate, persistent; stigmas capitate. Fruit a subglobose or an ovoid capsule opening by 2-3 valves at the apex.Seeds many, minute, oblong, granular, appendaged.
A mainly tropical family of only 1 genus. This family was previously included in Saxifragaceae from which it differs in its opposite leaves, insertion of the stamens on the margin of the epigynous disc, and the parietal placentas hanging from the roof of the ovary. In Saxifragaceae the leaves are alternate and placentation is axile. It also bears a close resemblance to certain species of Oldenlandia in the Rubiaceae, but can be recognised by the absence of stipules, the free petals and the numerous ovules attached to the placentas hanging from the roof of the unilocular ovary.
