IMO Practice Test — Morphology of Flowering Plants
6 Questions • 15 min • Olympiad level
15:00
Question 1 of 6
A plant has a fibrous root system, parallel venation and trimerous flowers. It is most likely a:
Monocot
Dicot
Gymnosperm
Fern
Explanation: Fibrous roots, parallel venation and trimerous flowers are typical monocot features.
Question 2 of 6
Carrot and sweet potato both store food, but the carrot is a modified root while the sweet potato is a modified root too — what general purpose do such modifications serve?
Storage of food (and water)
Climbing
Breathing
Photosynthesis only
Explanation: Tuberous/swollen roots are modified for storage of food and water.
Question 3 of 6
Why is the order of flower opening (acropetal vs basipetal) useful in classifying inflorescences?
It reflects whether the main axis keeps growing or ends in a flower
It shows the flower colour
It shows leaf number
It has no meaning
Explanation: Acropetal opening = racemose (axis grows on); basipetal = cymose (axis ends in a flower).
Question 4 of 6
A floral formula and a floral diagram together are useful because they:
Summarise the number, fusion and arrangement of floral parts compactly
Show the root system
Indicate the fruit's taste
Replace the need for the flower
Explanation: They compactly record the symmetry, whorls, numbers, fusion and position of floral parts.
Question 5 of 6
The Fabaceae are agriculturally vital partly because their roots host bacteria that:
Fix atmospheric nitrogen, enriching the soil
Produce antibiotics
Cause disease
Make the fruit a berry
Explanation: Legume root nodules house nitrogen-fixing bacteria that enrich the soil.
Question 6 of 6
Two flowers both have fused petals and axile placentation, but one is regular (actinomorphic) and the other is irregular (zygomorphic). The zygomorphic one is more likely a:
Fabaceae (pea) flower
Solanaceae (tomato) flower
Liliaceae (onion) flower
Grass flower
Explanation: Fabaceae flowers are zygomorphic (papilionaceous), unlike the actinomorphic Solanaceae/Liliaceae.