PLANTS: annual or perennial herbs, shrubs, one species a small tree; hairs diverse, often barbed, sometimes dendritic or stinging, usually unicellular and silicified or calcified. STEMS: mostly erect, usually brittle; mature epidermis often white. LEAVES: exstipulate, ours alternate, simple and usually toothed or lobed. I INFLORESCENCE: cymose or sometimes racemose. FLOWERS: perfect, actinomorphic, epigynous or rarely perigynous, the hypanthium often extending slightly beyond the ovary as a short tube; sepals 5 (in ours), usually persistent; petals 5 (in ours), sometimes appearing more numerous by development ofpetaloid staminodia, free or connate; stamens (2), 5 or lO-many, free to epipetalous; pistil (in ours) 3- or 5-carpellate, unilocular; style 1, often persistent. FRUIT: a capsule or an achene. SEEDS: 1 and subapical or l-many and parietal; endosperm present or absent. NOTES: 15 genera, ca. 250 species, New World, except 1 genus in Afr. and Arabia, 1 in Marquesas Islands. Hufford, L. D. 1989. Nordic J. Bot. 9:217-227, and references therein. REFERENCES: Christy, Charlotte M. 1998. Loasaceae. J. Ariz. - Nev. Acad. Sci. 30(2): 96.