The characteristic feature of angiosperms is the <answer>flower</answer>. Flowers show remarkable variation in form and elaboration, and provide the most trustworthy external characteristics for establishing relationships among angiosperm species. The function of the <answer>flower</answer> is to ensure fertilization of the ovule and development of fruit containing seeds. The floral apparatus may arise terminally on a shoot or from the axil of a leaf (where the petiole attaches to the stem). Occasionally, as in violets, a <answer>flower</answer> arises singly in the axil of an ordinary foliage-leaf. More typically, the <answer>flower</answer>-bearing portion of the plant is sharply distinguished from the foliage-bearing or vegetative portion, and forms a more or less elaborate branch-system called an inflorescence.
What is the defining feature of angiosperms?
flower