LOOSA, in botany: A genus of the monogynia order, belonging to the polyandria class of plants. The calyx is pentaphyllous, superior; there are five sub-ovate, cucullated, and large petals; the nectarium consists of five leaves, gathered into a conical figure, each terminated by two filaments; the capsule is turbinated, unilocular, and trivalved at top; the seeds are very numerous; and there are three linear and longitudinal sinuses.