Family Solanaceae

NCERT grounding

NCERT Class 11 Biology, Chapter 5 (§5.9), describes Solanaceae as “a large family, commonly called as the ‘potato family’,” widely distributed in tropics, subtropics and even temperate zones. The textbook uses Solanum nigrum (makoi) as its illustrative plant and provides a labelled set of figures — flowering twig, flower, L.S. of flower, stamens, carpel and floral diagram. Every diagnostic character and the floral formula on this page is drawn directly from that NCERT account; the NIOS shoot-system chapter independently confirms the two highest-yield characters: epipetalous stamens in brinjal and axile placentation in tomato.

“Androecium: stamens five, epipetalous … Gynoecium: bicarpellary obliquely placed, syncarpous; ovary superior, bilocular, placenta swollen with many ovules, axile.”
— NCERT Class 11 Biology, §5.9 Solanaceae

The potato family in full

Solanaceae earns its common name from Solanum tuberosum, the potato, whose swollen underground stem feeds much of the world. The family is sometimes called the nightshade family after its many alkaloid-rich members, several of which are poisonous or pharmacologically potent. Cosmopolitan in distribution, it thrives across tropical, subtropical and temperate zones, which is partly why it supplies so many staple crops, spices and drugs at once.

For NEET the family is studied as a fixed checklist of vegetative and floral characters, ending in a floral formula and floral diagram. The vegetative side establishes the habit and the leaf arrangement; the floral side carries the high-yield diagnostics — the union of sepals and petals, the epipetalous stamens, and the obliquely placed bicarpellary ovary with axile placentation. Each of these has appeared in NEET either as a direct fact or as a distractor against Fabaceae and Liliaceae.

Vegetative characters

The plants are mostly herbs, shrubs and rarely small trees. The stem is herbaceous and rarely woody, aerial, erect, cylindrical, branched, solid or hollow, and either hairy or glabrous; in potato the stem is famously modified into an underground tuber. The leaves are alternate, simple (rarely pinnately compound), exstipulate, with reticulate venation. The root system is a tap root, as expected of a dicot family.

Floral characters

The inflorescence is solitary, axillary or cymose (cymose as in Solanum). The flower is bisexual and actinomorphic — radially symmetrical — and this radial symmetry is itself a NEET point, since it sets Solanaceae apart from the zygomorphic Fabaceae. The four whorls follow a tight pattern that you should be able to recite from memory.

The gynoecium repays a closer look. The two carpels are fused (syncarpous) and the ovary is superior and bilocular. The placenta is swollen and bears many ovules attached to the central axis where the carpel margins meet — this is the textbook definition of axile placentation. Crucially, the bicarpellary ovary is described as obliquely placed: the two carpels are not aligned in the median plane of the flower but tilted relative to the mother axis, a feature unique enough to be a stand-alone exam fact. After fertilisation the ovary ripens into a berry (tomato, brinjal) or a capsule (Datura), and the seeds are many and endospermous.

The floral formula

The floral formula compresses every floral character into a single line of symbols. For Solanaceae the flower is bisexual and actinomorphic, with five united sepals, five united petals, five epipetalous stamens and a bicarpellary syncarpous superior ovary. Written out in the standard symbols:

Two conventions in the formula carry marks. The brackets around the gynoecium number — G(2) — denote that the two carpels are fused (syncarpous); without brackets, G2 would mean apocarpous. The bar drawn over the corolla and androecium denotes adhesion — here, the epipetalous attachment of stamens to the petals. The superior position of the ovary is marked by a line under the G. Reading these marks correctly is exactly what NEET tested in 2021, when match-the-column required candidates to map families to their floral formulae.

Economic importance

Few families touch daily life as broadly as Solanaceae, which is why NCERT devotes a separate note to its uses. The members span the kitchen, the spice rack, the pharmacy and the garden, and these categories — food, spice, medicine, fumigatory, ornamental — are precisely the buckets NEET expects you to fill with the right genus.

Worked examples

Common confusion & NEET traps