Model Answer
0 min readIntroduction
Plant taxonomy, the science of naming, describing and classifying organisms, relies heavily on morphological characteristics, particularly floral features. Verbenaceae (now often included within the Lamiaceae family) and Liliaceae are two distinct flowering plant families with significant economic and ecological importance. Understanding their identifying characters, floral diagrams, and floral formulas is crucial for accurate plant identification and phylogenetic studies. This answer will detail these aspects for both families, providing a comprehensive overview for botanical understanding.
Verbenaceae (or Lamiaceae subfamily Lamioideae)
Verbenaceae, often now considered a subfamily (Lamioideae) within Lamiaceae, is a family of flowering plants known for its aromatic herbs and shrubs.
Identifying Characters:
- Habit: Mostly herbs, shrubs, and small trees.
- Leaves: Opposite, simple, usually toothed.
- Inflorescence: Usually cymose or verticillate spikes or panicles.
- Calyx: Usually 5-lobed or -toothed, persistent.
- Corolla: Bilabiate (two-lipped), often with a tubular base.
- Androecious parts: Stamens 4, didynamous (two long and two short), epipetalous (attached to the petals).
- Gynoecious parts: Ovary superior, bicarpellary, syncarpous (united carpels), with a single locule. Fruit is a schizocarp.
Floral Diagram:
A floral diagram for Verbenaceae would show a superior ovary, a bilabiate corolla, didynamous stamens, and a five-lobed calyx. (A visual diagram would be included here in an exam setting)
Floral Formula:
The floral formula for a typical Verbenaceae flower is: % ⚥ (5) C5 A4 G(2)
Where:
- % - Actinomorphic (radially symmetrical)
- ⚥ - Bisexual
- (5) - Number of floral parts in multiples of 5
- C5 - 5 sepals
- A4 - 4 stamens
- G(2) - 2 carpels (superior ovary)
Liliaceae
Liliaceae, the lily family, is a family of monocotyledonous flowering plants. It is characterized by its bulbous or rhizomatous habit and showy flowers.
Identifying Characters:
- Habit: Mostly perennial herbs with bulbs, corms, or rhizomes.
- Leaves: Usually linear or lanceolate, often arranged in a spiral or whorl.
- Inflorescence: Solitary flowers or racemes, panicles, or umbels.
- Perianth: Tepals (undifferentiated sepals and petals) usually 6, arranged in two whorls of three.
- Androecious parts: Stamens 6, usually attached to the tepals.
- Gynoecious parts: Ovary superior, tricarpellary, syncarpous, with 3 locules. Fruit is a capsule.
Floral Diagram:
A floral diagram for Liliaceae would show a superior ovary, 6 tepals, 6 stamens, and a tricarpellary gynoecium. (A visual diagram would be included here in an exam setting)
Floral Formula:
The floral formula for a typical Liliaceae flower is: P3+3 A3+3 G(3)
Where:
- P3+3 - 3 sepals + 3 petals (tepals)
- A3+3 - 3 stamens
- G(3) - 3 carpels (superior ovary)
Comparative Table: Verbenaceae vs. Liliaceae
| Feature | Verbenaceae (Lamiaceae Lamioideae) | Liliaceae |
|---|---|---|
| Habit | Herbs, shrubs, small trees | Perennial herbs (bulbs, corms, rhizomes) |
| Leaves | Opposite, simple, toothed | Linear/lanceolate, spiral/whorled |
| Perianth | Calyx (5-lobed) & Corolla (bilabiate) | Tepals (6) |
| Stamens | 4, didynamous | 6 |
| Carpels | 2, syncarpous | 3, syncarpous |
| Fruit | Schizocarp | Capsule |
Conclusion
In conclusion, Verbenaceae and Liliaceae represent distinct plant families with unique morphological characteristics. Verbenaceae, often included within Lamiaceae, exhibits bilabiate corollas and a schizocarp fruit, while Liliaceae is characterized by its tepals, superior ovary, and capsule fruit. Understanding their floral diagrams and formulas is essential for accurate taxonomic identification and appreciating the diversity within the plant kingdom. Further research into their phylogenetic relationships continues to refine our understanding of their evolutionary history.
Answer Length
This is a comprehensive model answer for learning purposes and may exceed the word limit. In the exam, always adhere to the prescribed word count.