Haloragaceae
Herbs or subshrubs, mostly hydrophytic and often aquatic; stems with monostelic anatomy. Lvs alternate, opposite or whorled, exstipulate, the submerged lvs often finely dissected. Fls solitary and axillary, or in spikes or panicles, small, ⚥ or unisexual, actinomorphic. Calyx tube adnate to ovary; lobes 2, 4 or 0. Petals 2, 4-(8) or 0, valvate or nearly so, reflexing, often caducous. Stamens 2, 4 or 8, antipetalous, epipetalous; anthers basifixed. Ovary inferior, (2)-4-celled; each cell with 1-2 ovules; ovules pendulous from apex. Styles (2)-4, free; stigmas capitate and sometimes fimbriate. Fr. usually a small, often winged, rugose or tuberculate nut, sometimes a schizocarp separating into 1-seeded mericarps (nutlets). Seeds endospermic; embryo straight.
Key
8 genera, c. 100 spp., mainly S. Hemisphere, especially Australia.
Allan (1961) included Gunnera L. in Haloragaceae but this genus is now generally considered to form a separate and unrelated family (Dahlgren, R. M. T., Nord. J. Bot. 3: 119-149 (1983).
