Important Families of Flowering Plants: Fabaceae, Solanaceae, Liliaceae & Poaceae
Important Families of Flowering Plants: Fabaceae, Solanaceae, Liliaceae & Poaceae
Plant families are a high-yield topic for NEET Biology. Questions can be asked directly from floral characters, inflorescence, calyx, corolla, androecium, gynoecium, ovary position, floral formula, floral diagram and important examples.
Among the flowering plant families commonly studied in school and NEET Biology, Fabaceae, Solanaceae, Liliaceae and Poaceae are especially important.
Major Families of Flowering Plants
| Family | Common Name | Important Examples |
|---|---|---|
| Fabaceae | Pea family | Pea, gram, bean, soybean |
| Solanaceae | Potato family | Potato, tomato, chilli, tobacco |
| Liliaceae | Lily family | Lily, Aloe, Asparagus |
| Poaceae | Grass family | Wheat, rice, maize, bamboo |
1. Family Fabaceae
Fabaceae is commonly known as the pea family. It includes many economically important plants used as pulses, vegetables, oilseeds and ornamental plants.
Important Examples of Fabaceae
- Pea (Pisum sativum)
- Gram (Cicer arietinum)
- Bean
- Soybean
- Groundnut
- Sunflower? No — sunflower belongs to Asteraceae.
- Clitoria
Vegetative Characters
The root system is generally tap root. Many members of Fabaceae form root nodules containing nitrogen-fixing bacteria such as Rhizobium.
The leaves are generally alternate and often compound. Leaves may be pinnate, trifoliate or otherwise modified depending on the plant.
Inflorescence
The inflorescence can vary among members of the family. In many commonly studied examples, flowers occur in racemose or related arrangements.
Flower
The flowers are generally bisexual, zygomorphic and pentamerous.
Calyx
The five sepals are generally fused, forming a gamosepalous calyx.
Corolla
The corolla is typically papilionaceous and consists of five petals:
- One large posterior petal — standard or vexillum
- Two lateral petals — wings
- Two anterior petals — fused to form the keel
The arrangement is known as descending imbricate aestivation.
Androecium
There are usually 10 stamens. In the typical papilionaceous condition, nine stamens are fused while one remains free.
This condition is called diadelphous.
Gynoecium
The gynoecium is generally monocarpellary. The ovary is superior and unilocular with marginal placentation.
Fruit
The fruit is generally a legume.
Floral Formula
% ⚥ K(5) C1+2+(2) A(9)+1 G1
Key Fabaceae features: zygomorphic flower, papilionaceous corolla, vexillum, wings, keel, diadelphous stamens and marginal placentation.
2. Family Solanaceae
Solanaceae is commonly known as the potato family. It includes several important food, medicinal and ornamental plants.
Important Examples of Solanaceae
- Potato (Solanum tuberosum)
- Tomato (Solanum lycopersicum)
- Brinjal / Eggplant (Solanum melongena)
- Chilli (Capsicum)
- Tobacco (Nicotiana tabacum)
- Petunia
- Datura
Vegetative Characters
Members of Solanaceae are generally herbs or shrubs, although some may have other growth forms.
The leaves are generally alternate and simple, without stipules.
Inflorescence
The inflorescence may be cymose or flowers may occur singly, depending on the genus.
Flower
The flowers are generally bisexual, actinomorphic and pentamerous.
Calyx
The five sepals are united, forming a persistent gamosepalous calyx.
Corolla
The five petals are fused, forming a gamopetalous corolla. The corolla is usually rotate or funnel-shaped depending on the genus.
Androecium
There are usually five stamens. The stamens are epipetalous, meaning they are attached to the petals.
Gynoecium
The gynoecium is bicarpellary and syncarpous. The ovary is superior and generally bilocular with axile placentation.
Fruit
The fruit may be a berry or a capsule depending on the genus.
Floral Formula
⊕ ⚥ K(5) C(5) A5 G(2)
3. Family Liliaceae
Liliaceae is commonly known as the lily family. It represents an important family of monocotyledonous flowering plants.
Important Examples of Liliaceae
- Lily (Lilium)
- Aloe
- Asparagus
- Colchicum
Vegetative Characters
Members are generally perennial herbs with underground structures such as bulbs, rhizomes or corm-like organs in different genera.
The leaves are generally simple, elongated and parallel-veined.
Inflorescence
Inflorescence may vary. Flowers can occur singly or in clusters depending on the genus.
Flower
The flowers are generally bisexual, actinomorphic and trimerous.
Perianth
The perianth consists of six tepals arranged in two whorls of three each.
The tepals are generally petaloid and may be free or united depending on the genus.
Androecium
There are generally six stamens, arranged in two whorls of three.
Gynoecium
The gynoecium is generally tricarpellary and syncarpous. The ovary is superior and commonly shows axile placentation.
Fruit
The fruit may be a capsule or berry depending on the genus.
Floral Formula
⊕ ⚥ P3+3 A3+3 G(3)
4. Family Poaceae
Poaceae is commonly known as the grass family or Gramineae. It is one of the most economically important families of flowering plants.
Important Examples of Poaceae
- Wheat (Triticum)
- Rice (Oryza)
- Maize (Zea mays)
- Sugarcane (Saccharum)
- Bamboo
- Barley
Vegetative Characters
Most members are herbs with characteristic jointed stems. The nodes are solid in many grasses while internodes are commonly hollow.
Leaves are generally alternate and have a long leaf sheath and a linear leaf blade.
Inflorescence
The basic unit of the grass inflorescence is the spikelet.
Spikelets may be arranged into different types of inflorescences such as spikes, racemes or panicles.
Flower
Grass flowers are generally small and inconspicuous. They are usually bisexual and wind-pollinated.
Perianth
The perianth is highly reduced and is represented by structures called lodicules.
Androecium
The number of stamens is commonly three in many grasses. The anthers are versatile and adapted to wind pollination.
Gynoecium
The gynoecium is generally monocarpellary in appearance but develops from a tricarpellary origin in the typical grass flower. The ovary is superior, unilocular and contains a single ovule.
Fruit
The characteristic fruit of grasses is a caryopsis.
Floral Formula
Br ⊕ ⚥ P2/3 A3 G(2)
Fabaceae vs Solanaceae vs Liliaceae vs Poaceae
| Character | Fabaceae | Solanaceae | Liliaceae | Poaceae |
|---|---|---|---|---|
| Symmetry | Zygomorphic | Actinomorphic | Actinomorphic | Generally reduced/inconspicuous |
| Flower type | Bisexual | Bisexual | Bisexual | Usually bisexual |
| Calyx / Perianth | 5 sepals | 5 fused sepals | 6 tepals | Lodicules |
| Stamens | 10, usually 9+1 | 5 | 6 | Usually 3 |
| Ovary | Superior | Superior | Superior | Superior |
| Placentation | Marginal | Axile | Axile | Basal |
| Typical fruit | Legume | Berry / Capsule | Capsule / Berry | Caryopsis |
High-Yield NEET Differences
Fabaceae
Zygomorphic → Papilionaceous corolla → Diadelphous stamens → Marginal placentation → Legume.
Solanaceae
Actinomorphic → Gamopetalous corolla → 5 epipetalous stamens → Superior ovary → Axile placentation.
Liliaceae
Monocot → Trimerous → 6 tepals → 6 stamens → Superior ovary → Axile placentation.
Poaceae
Spikelet → Lodicules → Usually 3 stamens → Versatile anthers → One ovule → Caryopsis.
Easy Memory Trick
SOLANACEAE: 5 fused petals + 5 epipetalous stamens + Axile
LILIACEAE: 3 + 3 tepals + 3 + 3 stamens + Monocot
POACEAE: Spikelet + Lodicules + Caryopsis
Frequently Asked Questions
Which family has a papilionaceous corolla?
Fabaceae has a characteristic papilionaceous corolla consisting of standard, wings and keel.
Which family has diadelphous stamens?
The typical papilionaceous condition of Fabaceae has nine fused stamens and one free stamen.
Which family has epipetalous stamens?
Solanaceae commonly has five epipetalous stamens.
Which family is characterized by six tepals?
Liliaceae typically has six tepals arranged in two whorls of three.
What is the basic inflorescence unit of Poaceae?
The basic unit is the spikelet.
What is the fruit of Poaceae?
The characteristic fruit is a caryopsis.
Which family contains wheat and rice?
Both wheat and rice belong to the family Poaceae.
Final Takeaway for NEET
Plant families become much easier when you compare their diagnostic characters instead of memorizing long paragraphs.
For NEET, focus especially on symmetry, aestivation, number and attachment of stamens, ovary position, placentation, fruit type, floral formula and important examples.
Fabaceae = Papilionaceous
Solanaceae = Epipetalous 5 stamens
Liliaceae = 3 + 3
Poaceae = Spikelet + Caryopsis
