Questions - Answers

VERY SHORT ANSWER TYPE QUESTIONS

1. What is natural system of plant classification? Name the scientists who followed it.
A: The system of classification that considers all possible morphological characters and their natural relationships is called natural system of classification.
Bentham and Hooker followed this system.
 

2. Explain the scope and significance of Numerical taxonomy.
A: Numerical taxonomy can be used to evaluate differences and similarities between taxonomic groups using mathematics and computers.
As this method uses numbers and codes it is easy and quick process and can be used for hundreds of characters at a time.
 

3. Write the floral formula of solanum plant.
A: Br, Ebrl, +, ,K(5), C(5), A5, G(2)

4. Give the technical description of ovary of Solanum nigrum.
A: The ovary of Solanum nigrum is bi or uni locular, superior ovary with many ovules on axile placenta. The carpels are arranged obliquely at 450. Style is terminal and stigma capitate. 
 

SHORT ANSWER TYPE QUESTIONS
1. Write a brief note on semi technical description of a typical flowering plant.

A: Description of parts of a flowering plant is necessary for characterization, identification and classification of plants. Technical terms are used to describe the habit, habitat, vegetative characters (roots, stem and leaves ) and floral characters like inflorescence, flower in general and detail, fruit, seed, pollination etc.
A typical flowering plant is described using technical terminology as follows:
Habit: Herb/Shrub/Tree/Climber etc.
Habitat: Mesophyte/xerophytes/hydrophyte etc.
Vegetative characters:
a)  Root: taproot/fibrous root/ modifications if any
b)  Stem: woody/herbaceous/climber/creeper etc.
c)   Leaf: radical/cauline/venation/phyllotaxy

Floral characters:
a)  Inflorescence: Position and type
b)  Flower: General description like presence or absence of bracts, bracteoles etc, merosity, sexuality, symmetry and type based on position of the ovary
c)  Calyx: No. of sepals, union, aestivation.
d)  Corolla: No. of petals, union, aestivation etc.
e)  Androecium: No. of stamens, their union, anthers etc.
f)  Gynoecium: No. and union of carpels, No. of locules, position of ovary, placentation etc.
g)  Pollination: Self or cross pollination, contrivances and mechanisms.
h)  Fruit: Type
i)  Seed: Dicot or monocot, endospermic or non endospermic.
 

2. Explain floral formula.
A: Floral diagram and floral formula are used to describe the flower precisely.
The floral formula contains the following 8 elements:
Bract present or absent - Br/Ebr
Bracteoles present or absent - Brl/Ebrl

Symmetry - Actinomorphic (+)/Zygomorphic (%)
Sexuality - unisexual male / unisexual female / bisexual
Calyx (K)- number of sepals, gamosepalous / polysepalous
Corolla (C) - number of petals, gamopetalous / polypetalous.
(In some plants there is no distinction between calyx and corolla hence Perianth is denoted by P)
Androecium (A) - number of stamens, adhesion, cohesion if any.
Gynoecium (G) - number of carpels, syncarpous/apocarpous condition, superior or inferior ovary.
 

LONG ANSWER TYPE QUESTION
1. What is taxonomy? Give a brief account of different types of plant classification.

A: Taxonomy is the science of characterization, identification, nomenclature and classification of organisms. The term taxonomy was coined by A.P. de Candolle.
Types of Classification
* Based on the criteria followed for classification three types of classifications are recognized.
1. Artificial systems
2. Natural systems
3. Phylo genetic systems

* Artificial system is based on morphological characters like habit, colour, number and shape of leaves etc.
e.g.: 1. Theophrastus classified plants into herbs, shrubs and trees in his book 'Historia plantarum'.
        2. Linnaeus classified plants into 24 groups in his book 'Species plantarum'.

* Natural system is based on all possible morphological characters and natural relationships between plants.
e.g.: Bentham and Hooker’s system of classification in the book 'Genera Plantarum'.
They classified flowering plants into three classes and 202 natural orders or families.

* Phylogenetic system is based on evolutionary relationships considering primitive and advanced characters. 
e.g.: Engler and Prantl’s system.
* Other types of classifications include numerical taxonomy, cytotaxonomy and chemotaxonomy.