Dev studies a China rose flower in the school garden…
Contributed by StemPy LabTry it on paper first. A hint, the key idea and the worked solution are here when you need them.
Dev studies a China rose flower in the school garden. It has five free sepals, five free petals, and many stamens joined into one tube round the style. The petals overlap each other, each overlapping its neighbour on one side. The ovary sits above the other parts. (a) What is the union of stamens called? (b) Name the aestivation. (c) Name the position of the ovary. (d) Is the flower bisexual or unisexual?
Need a reminder? The key ideaShow
A flower has the calyx, corolla, androecium and gynoecium. Bisexual or unisexual; actinomorphic, zygomorphic or asymmetric. Hypogynous (superior ovary), perigynous (half inferior), epigynous (inferior). Aestivation: valvate, twisted, imbricate, vexillary. Stamens: filament and bilobed anther with four pollen sacs; epipetalous, epiphyllous, monoadelphous, diadelphous, polyadelphous. Carpel: ovary, style, stigma; apocarpous or syncarpous. Placentation: marginal, axile, parietal, free central, basal.
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. The stamens. Stamens united in one bundle are monoadelphous.
Step 2. The aestivation. Each petal overlaps the next in one direction, all round. This is twisted aestivation.
Step 3. The ovary. It sits above the other parts. The flower is hypogynous, and the ovary is superior.
Step 4. The sexes. It has stamens and carpels, so it is bisexual.
Answer: (a) monoadelphous; (b) twisted; (c) hypogynous, with a superior ovary; (d) bisexual.
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