Lesson 5 of 13 · 7 min
Racemose and cymose inflorescence
NCERT §5.4, Figures 5.7–5.8
On one mustard stalk, the lowest flowers have already made pods while buds are still opening at the top. On a jasmine bush the top flower is the oldest. Why do they open in opposite orders?
The lesson in notes
In short
A flower is a modified shoot. The shoot apical meristem turns into a floral meristem, the internodes stay short so the axis is condensed, and the apex produces floral appendages at successive nodes in place of leaves.
When a shoot tip itself becomes a flower, that flower is always solitary.
Inflorescence: the way flowers are arranged on the floral axis.
The two major types are defined by one question: does the apex turn into a flower, or does it keep growing?
Racemose: the main axis goes on growing, and flowers are borne on its sides in acropetal succession, so the oldest flowers are at the base and the youngest near the tip.
Cymose: the main axis ends in a flower, so its growth is limited, and the flowers open in basipetal order, the oldest at the top.
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Racemose versus cymose with diagrams
Transpicuous Learning · English · Lecture · Open on YouTube