BOTANY: Morphology and Taxonomy (BOTDSM-151T)
FYUG Even Semester Exam, 2024
Course No: BOTDSM-151T | Full Marks: 70 | Pass Marks: 28
SECTION-A (Answer any ten) 2 × 10 = 20 Marks
1. What is opposite decussate?
In opposite decussate phyllotaxy, two leaves are produced at each node. Each pair of leaves is placed at a right angle (90°) to the pair immediately above or below it, forming four vertical rows when viewed from the top.
2. What are the special types of inflorescence?
Special types of inflorescence do not follow the simple racemose or cymose patterns. Examples include:
- Cyathium: Found in Euphorbia.
- Hypanthodium: Found in Ficus.
- Verticillaster: Found in Ocimum.
3. Write a note on underground modified stem.
Underground stems are modified for food storage and perennation. They remain dormant during unfavorable conditions and produce aerial shoots when favorable. Common types include:
- Rhizome: (e.g., Ginger).
- Tuber: (e.g., Potato).
- Bulb: (e.g., Onion).
- Corm: (e.g., Colocasia).
4. Name two important herbaria of India with their acronym.
| Herbarium Name |
Acronym |
| Central National Herbarium, Kolkata |
CAL |
| Forest Research Institute, Dehradun |
DD |
5. Name two important flora of Assam.
- Flora of Assam by U.N. Kanjilal et al.
- Forest Flora of Lakhimpur.
6. Write about A. J. C. Bose Indian Botanic Garden.
Formerly known as the Royal Botanic Garden, it is located in Shibpur, Howrah. It was founded in 1787 by Robert Kyd. It is world-famous for The Great Banyan Tree and serves as a major center for botanical research and conservation in India.
7. What is binomial nomenclature? Who proposed it?
Binomial nomenclature is the formal system of naming species of living things by giving each a name composed of two parts: the Genus name and the specific epithet. It was proposed by Carolus Linnaeus.
8. What are the taxonomic ranks?
The taxonomic ranks in descending order of hierarchy are: Kingdom, Division (Phylum), Class, Order, Family, Genus, and Species.
9. What is typification?
Typification is the process of designating a specific specimen (Type) to act as the permanent reference point for a botanical name. If the original description is lost, the type specimen ensures the name remains attached to a physical plant entity.
10. What are the systems of classification?
Classification systems are categorized as:
- Artificial: Based on one or few superficial characters (e.g., Linnaeus).
- Natural: Based on overall morphological similarities (e.g., Bentham & Hooker).
- Phylogenetic: Based on evolutionary relationships (e.g., Engler & Prantl).
11. What is numerical taxonomy?
Numerical taxonomy is a classification system in biological systematics which deals with the grouping by numerical methods of taxonomic units based on their character states. It aims to create an objective classification using mathematical algorithms.
12. What is phylogenetic classification?
It is a system of classification based on the evolutionary history (phylogeny) of organisms. It reflects the genetic relationship and descent from common ancestors.
13. What are perianth and labellum?
- Perianth: The non-reproductive part of the flower that envelopes the reproductive organs, used when calyx and corolla are not distinct.
- Labellum: A modified petal (lip) found in Orchidaceae that often acts as a landing platform for pollinators.
14. Define verticillaster inflorescence.
A verticillaster is a complex inflorescence where a pair of condensed cymes arises at the axils of opposite leaves. The flowers appear in a false whorl around the stem at the node, characteristic of the Lamiaceae family.
15. Write the scientific names of two economically important species of Poaceae.
- Oryza sativa (Rice)
- Triticum aestivum (Wheat)
SECTION-B (Answer any five) 10 × 5 = 50 Marks
16. Describe the different types of modified tap root and adventitious roots. [10]
Roots are modified to perform functions other than absorption and anchorage, such as storage and support.
Modified Tap Roots (Storage):
- Conical: Broad at the base and tapers toward the apex (e.g., Carrot).
- Fusiform: Swollen in the middle and tapers at both ends (e.g., Radish).
- Napiform: Extremely swollen at the base, becoming spherical (e.g., Turnip).
Modified Adventitious Roots:
- Prop Roots: Grow vertically downward from horizontal branches to provide support (e.g., Banyan tree).
- Stilt Roots: Arise from the lower nodes of the stem to provide extra mechanical support (e.g., Maize, Sugarcane).
- Tuberous Roots: Swollen adventitious roots for food storage (e.g., Sweet Potato).
17. (a) Flower as a modified shoot; (b) Significance of Floral Formula and Diagram. [5+5]
(a) Flower as a modified shoot: A flower is considered a modified shoot where the internodes are highly condensed. The leaves of the shoot are modified into floral appendages like sepals, petals, stamens, and carpels. The thalamus represents the condensed axis (stem).
(b) Significance of Floral Formula & Diagram:
- Floral Diagram: Provides a top-down visual representation of the flower's structure, showing the number of parts, their arrangement (aestivation), and adhesion or cohesion.
- Floral Formula: A shorthand representation using symbols to describe the sexuality, symmetry, and number of floral parts (K, C, A, G).
- Together, they allow for rapid comparison and identification of plant families.
18. Herbarium: Preparation and Role. [1+5+4]
Definition: A herbarium is a collection of dried, pressed, and preserved plant specimens arranged according to a recognized system of classification.
Herbarium Preparation:
- Field Collection: Collecting healthy specimens with flowers/fruits.
- Pressing: Placing specimens between blotting papers to remove moisture.
- Drying: Changing papers frequently to prevent fungal growth.
- Poisoning: Treating with chemicals like Mercuric Chloride to prevent insect attack.
- Mounting: Attaching the specimen to a standard herbarium sheet (29 x 41.5 cm).
- Labeling: Providing data on the bottom right corner (Name, Date, Place, Collector).
Role of Herbarium:
- Acts as a repository of plant biodiversity.
- Serves as a reference center for identifying unknown plants.
- Provides data for monographic and floristic studies.
- Preserves "Type Specimens" for nomenclature.
20. ICN: Principles and Rules of Binomial Nomenclature. [1+6+3]
ICN: International Code of Nomenclature for algae, fungi, and plants.
Six Principles of ICN:
- Botanical nomenclature is independent of zoological nomenclature.
- Application of names is determined by means of nomenclatural types.
- Nomenclature is based on priority of publication.
- Each taxonomic group can bear only one correct name.
- Scientific names are treated as Latin regardless of their origin.
- Rules of nomenclature are retroactive unless expressly limited.
Rules of Binomial Nomenclature:
- The first word (Genus) starts with a capital letter; the second (Species) starts with a small letter.
- Names must be underlined when handwritten or italicized when printed.
- The name of the author who first described the species is written after the specific epithet (e.g., Mangifera indica L.).
22. Bentham and Hooker's System of Classification. [1+7+2]
Natural System: A system based on the maximum number of natural characters and affinities.
Bentham and Hooker's System: They classified Seed Plants (Phanerogams) into three classes: Dicotyledones, Gymnospermae, and Monocotyledones. Dicotyledones were further divided into Polypetalae, Gamopetalae, and Monochlamydeae.
Merits: Highly practical for herbarium arrangement; based on actual observation of specimens.
Demerits: Placing Gymnosperms between Dicots and Monocots is phylogenetically incorrect; some advanced families were placed in primitive groups.
24. Asteraceae: Range of Characters and Economic Importance. [4+4+2]
Vegetative Characters: Mostly herbs; leaves usually alternate or opposite, often exstipulate.
Floral Characters: Inflorescence is a Head or Capitulum surrounded by an involucre of bracts. Flowers (florets) are often of two types: Central Tubular Disc florets and Peripheral Ligulate Ray florets. Calyx is modified into Pappus (hair-like) for seed dispersal. Stamens are Syngenesious (anthers fused, filaments free).
Economically Important Species:
- Helianthus annuus (Sunflower) - Oil seed.
- Tagetes erecta (Marigold) - Ornamental.