Biology · Morphology of Flowering Plants · NEET
Ray florets have an INFERIOR ovary. They are epigynous flowers. In an epigynous flower the margin of the thalamus grows upward and encloses the ovary completely, fusing with it. So the other floral parts (calyx, corolla, androecium) arise ABOVE the ovary. When the ovary is below the other parts like this, it is called inferior. NCERT gives the ray florets of sunflower as a direct example (along with guava and cucumber).
A sunflower head has two floret types. Ray florets sit at the outer edge; they are flat and strap-like (like petals) and are often the showy, attracting part. Disc florets sit in the centre; they are small and tubular. In NEET, the key tested point is that the ray florets of sunflower are epigynous with an inferior ovary. Both are true florets, not petals.
A sunflower is NOT a single flower. What looks like one big flower is actually an inflorescence called a capitulum (head). It is made of many tiny florets packed on a flat receptacle. The outer strap-like ones are ray florets and the inner tubular ones are disc florets. This is why the sunflower family is called Asteraceae (the composite family).
A capitulum (also called a head) is an inflorescence where many small sessile florets are crowded together on a flat or slightly convex receptacle, giving the look of a single flower. Sunflower and marigold show this. For NEET, remember: capitulum is the arrangement, ray florets and disc florets are the two floret types found inside it.
Ray florets are EPIGYNOUS, not hypogynous. Epigynous means the ovary is inferior (thalamus fused over the ovary, other parts above it). Hypogynous would mean a SUPERIOR ovary (gynoecium highest, other parts below), like in mustard or brinjal. A common NEET trap prints 'hypogenous' as a distractor, but the correct answer for ray florets is inferior ovary.
Ray florets have
Match the placental types (Column-I) with their examples (Column-II). Column-I: (a) Basal, (b) Axile, (c) Parietal, (d) Free central. Column-II: (i) Mustard, (ii) China rose, (iii) Dianthus, (iv) Sunflower.
Try the real previous-year questions from this chapter — each with the answer and a full solution.
Because the flower is epigynous. The thalamus margin grows up and fuses around the ovary, so the calyx, corolla and androecium all arise above the ovary. When the ovary lies below the other parts, it is inferior.
Sunflower belongs to family Asteraceae (also called Compositae). This family is known for the capitulum inflorescence made of ray florets and disc florets.
Sunflower shows basal placentation. The placenta is at the base of the ovary and a single ovule is attached to it. This is a common NEET matching point.
For NEET at the NCERT level, focus on the tested facts: ray florets are strap-like and often outer/showy, disc florets are tubular and central, and the ray florets of sunflower are epigynous with an inferior ovary. NCERT does not require you to memorise fertility details of each floret.
