Two climbers grow along the school wall…
Contributed by StemPy LabTry it on paper first. A hint, the key idea and the worked solution are here when you need them.
Two climbers grow along the school wall. On plant X the oldest flower is at the bottom of the stalk, and new buds keep appearing at the top. On plant Y the flower at the top of the stalk opened first, and the younger ones are lower down. (a) Name the type of inflorescence of each plant. (b) What happens to the tip of the main axis in each? (c) Name the order in which the flowers open on plant X.
Need a reminder? The key ideaShow
An inflorescence is the arrangement of flowers on the floral axis. Racemose: the main axis continues to grow, flowers open in acropetal order, the oldest at the base and the youngest at the tip. Cymose: the main axis ends in a flower, growth is limited, flowers open in basipetal order. The pedicel is the stalk of one flower; the peduncle is the stalk of the cluster.
The worked solution
Have you tried it?
Work it out on paper first. It is fine to get stuck or make a mistake: that is how we learn. When you are ready, go through the solution one step at a time, and check each step against your own.
Step 1. Plant X. The oldest flower is at the base and new flowers are added at the tip. So the main axis continues to grow. The inflorescence is racemose.
Step 2. Plant Y. The oldest flower is at the top, so the axis ended in a flower. Its growth is limited. The inflorescence is cymose.
Step 3. The order on X. The flowers open acropetally: from the base towards the tip.
Answer: (a) X is racemose, Y is cymose; (b) the tip keeps growing in X and ends in a flower in Y; (c) acropetal order.
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