in botany: A genus of the polyandria order, belonging to the polyadelphia clas of plants. The calyx is a monophyllous perianthium; the corolla has five petals growing to the calyx; the stamens are conjoined in five bodies; the germ is roundish; the style brittle, the length of the stamens. The fruit is a roundish apple everywhere murredicated; the seeds have a mucous orilla.