Context: The characteristic feature of angiosperms is the flower. 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 flower 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 flower arises singly in the axil of an ordinary foliage-leaf. More typically, the flower-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.

Question: What is the defining feature of angiosperms?
Answer: flower

Question: What characteristic flowers show variation in?
Answer: form and elaboration

Question: What do flowers provide the best external feature for doing?
Answer: establishing relationships among angiosperm species

Question: What is it the function of the flower to ensure fertilization of?
Answer: the ovule

Question: What is the name of a branch system?
Answer: inflorescence

Question: What is a main feature of vegatative portion of a plant?
Answer: Unanswerable

Question: What does the foliage-bearing part of the plant form to bear flowers?
Answer: Unanswerable

Question: What are some things that an elaborate branch system shows?
Answer: Unanswerable

Question: What does fruit with seeds provide to establish relationships among species?
Answer: Unanswerable

Question: What is the function of the petiole?
Answer: Unanswerable