Glossostigma
Nova Acta Phys.-Med. Acad. Caes. Leop.-Carol. Nat. Cur. 18: 355. 1836. name conserved
Herbs, annual or perennial, aquatic, mat-forming; stolons horizontal. Stems functionally stolons. Leaves on stolons, opposite; petiole absent [present]; blade fleshy, margins entire, obscurely uninerved (midvein). Inflorescences axillary, flowers solitary; bracts absent. Pedicels absent or present, longer or shorter than calyces; bracteoles absent. Flowers [monomorphic] dimorphic (perianth), erect or sessile; sepals 3[4], calyx radially or bilaterally symmetric, campanulate or urceolate, lobes oblong, adaxial lobe longer; petals 0 or [3–]5, corolla fugacious, white [suffused with blue, pink, or purple], bilaterally symmetric, weakly bilabiate, short-funnelform, abaxial lobes 3, adaxial 2, smaller; stamens 2[4], equal [didynamous], filaments glabrous; staminode 0; ovary 2-locular, placentation axile; stigma broad, flaplike, or relatively small. Fruits capsules, dehiscence loculicidal. Seeds 12–73[100], brown, flattened, wings absent. x = 5.
Distribution
Introduced; Asia, Africa, Pacific Islands (New Zealand), Australia.
Discussion
Species 7 or 8 (1 in the flora).
Chromosome counts from New Zealand (E. J. Beuzenberg and J. B. Hair 1983; P. J. de Lange et al. 2004) indicate a base number of x = 5 for Glossostigma. An anomalous count (2n = 32) has been reported for G. diandrum (Linnaeus) Kuntze from Bangladesh (see M. O. Rahman 2006).