Biology · Morphology of Flowering Plants · NEET
The formula is: Actinomorphic (radial symmetry), Bisexual, K(5) C(5) A5 G(2). K(5) means 5 sepals fused (calyx gamosepalous). C(5) means 5 petals fused (corolla gamopetalous). A5 means 5 stamens, and they sit on the petals (epipetalous). G(2) means the gynoecium has 2 fused carpels with a superior ovary (a line above G means superior). For NEET, remember the pattern 5-5-5 for calyx, corolla and androecium.
The ovary in Solanaceae is superior. This means the sepals, petals and stamens are attached below the ovary (a hypogynous flower). In the floral formula this is written as G with a line ABOVE it. NEET traps students by saying 'inferior' as a distractor, so lock in: Solanaceae = superior ovary. Brinjal, tomato and Solanum all show a superior ovary.
Epipetalous means the stamens are attached to (grow out of) the petals, not the thalamus. In Solanaceae the 5 stamens sit on the corolla tube. This is different from Fabaceae (diadelphous, fused into bundles) and Liliaceae (epiphyllous/epitepalous, attached to tepals). NEET asks you to link the family to its stamen attachment, so remember: Solanaceae stamens = epipetalous, 5 in number.
Solanaceae is BICARPELLARY (2 carpels) with an obliquely placed septum, giving a bilocular ovary with swollen axile placenta. Liliaceae is TRICARPELLARY (3 carpels), syncarpous, with a trilocular ovary and axile placentation. NEET 2016 asked which family has a tricarpellary syncarpous gynoecium and the answer was Liliaceae, NOT Solanaceae. So carpel number is the quick separator: Solanaceae = 2, Liliaceae = 3.
The septum is the wall that divides the ovary into chambers. In Solanaceae this wall is placed at a slant (oblique) instead of straight, so the two chambers lie diagonally. This obliquely placed septum is a diagnostic (unique identifying) feature of Solanaceae. NEET has directly asked 'bicarpellary ovary with obliquely placed septum is seen in?' and the answer was Solanum, a Solanaceae plant.
Solanaceae shows axile placentation. The ovary is bilocular (2 chambers) and the ovules are attached to a central axis where the septa meet. The placenta is swollen and bears many ovules. Other axile examples in NCERT are china rose, tomato and lemon. Petunia (a Solanaceae member) also shows axile placentation.
NEET examples include potato, tomato, brinjal (eggplant), chilli, tobacco (Nicotiana), Petunia, Datura, Withania (Ashwagandha) and Solanum nigrum (makoi). It is called the 'potato family'. Many are food crops, some are medicinal, and a few (Datura, tobacco) are drug/ornamental plants. Knowing 2-3 examples helps you match the family in floral formula questions.
Identify the correct floral formula of family Solanaceae.
Which of the following are characteristic features of the Solanaceae family? (a) Flowers are bisexual and actinomorphic; (b) Calyx has five sepals and is united; (c) Androecium has five stamens and is epipetalous; (d) Ovary is inferior.
Bicarpellary ovary with obliquely placed septum is seen in:
Try the real previous-year questions from this chapter — each with the answer and a full solution.
Actinomorphic (radially symmetric). It can be cut into two equal halves along any plane through the centre. This is different from Fabaceae, which is zygomorphic (only one plane gives equal halves).
Two carpels (bicarpellary), and they are fused (syncarpous). The ovary is bilocular with an obliquely placed septum and axile placentation.
Because the potato (Solanum tuberosum) is its best-known member. Other common members are tomato, brinjal, chilli, tobacco, Petunia and Datura.
The corolla shows valvate aestivation, meaning the 5 petals just touch at their edges without overlapping.
They are bisexual, containing both the androecium (stamens) and gynoecium (carpels) in the same flower.
