Biology MORPHOLOGY OF FLOWERING PLANTS

SEMI-TECHNICAL DESCRIPTION OF A TYPICAL FLOWERING PLANT

Various morphological features are used to describe a flowering plant. The description has to be brief, in a simple and scientific language and presented in a proper sequence. The plant is described beginning with its habit, vegetative characters – roots, stem and leaves and then floral characters inflorescence and flower parts. After describing various parts of plant, a floral diagram and a floral formula are presented. The floral formula is represented by some symbols. In the floral formula, Br stands for bracteate K stands for calyx , C for corolla, P for perianth, A for androecium and G for Gynoecium, G for superior ovary and G for inferior ovary, for male, for female , for bisexual plants, ⊕ for actinomorphic and for zygomorphic nature of flower. Fusion is indicated by enclosing the figure within bracket and adhesion by a line drawn above the symbols of the floral parts.

A floral diagram provides information about the number of parts of a flower, their arrangement and the relation they have with one another . The position of the mother axis with respect to the flower is represented by a dot on the top of the floral diagram. Calyx, corolla, androecium and gynoecium are drawn in successive whorls, calyx being the outermost and the gynoecium being in the centre.
Floral formula also shows cohesion and adhesion within parts of whorls and in between whorls. The floral diagram and floral formula in Figure represents the mustard plant (Family: Brassicaceae).

DESCRIPTION OF SOME IMPORTANT FAMILIES

# Fabaceae- This family was earlier called Papilonoideae, a subfamily of family Leguminosae. It is distributed all over the world.

# Vegetative Characters - Trees, shrubs, herbs; root with root nodules
Stem - erect or climber
Leaves - alternate, pinnately compound or simple; leaf base, pulvinate; stipulate; venation reticulate.

# Floral characters
Inflorescence : racemose
Flower : bisexual, zygomorphic
Calyx : sepals five, gamosepalous; imbricate aestivation
Corolla : petals five, polypetalous, papilionaceous, consisting of a posterior standard, two lateral wings, two anterior ones forming a keel (enclosing stamens and pistil), vexillary aestivation
Androecium : ten, diadelphous, anther dithecous
Gynoecium : ovary superior, mono carpellary, unilocular with many ovules, style single
Fruit : legume;
Seed : one to many, non-endospermic
Floral Formula: ⊕ K(5) C1+2+(2) A(9)+1 G1

# Economic importance - Many plants belonging to the family are sources of pulses (gram, arhar, sem, moong, soyabean; edible oil (soyabean, groundnut); dye (indigofera); fibres (sunhemp); fodder (Sesbania, Trifolium), ornamentals (lupin, sweet pea); medicine (muliathi).

Solanaceae

It is a large family, commonly called as the ‘potato family’. It is widely distributed in tropics, subtropics and even temperate zones.

# Vegetative Characters - Plants mostly, herbs, shrubs and small trees
Stem : herbaceous rarely woody, aerial; erect, cylindrical, branched, solid or hollow, hairy or glabrous, underground stem in potato (Solanum tuberosum)
Leaves : alternate, simple, rarely pinnately compound, exstipulate; venation reticulate

# Floral Characters - Inflorescence : Solitary, axillary or cymose as in Solanum
Flower : bisexual, actinomorphic
Calyx : sepals five, united, persistent, valvate aestivation
Corolla : petals five, united; valvate aestivation
Androecium : stamens five, epipetalous
Gynoecium : bicarpellary, syncarpous; ovary superior, bilocular, placenta swollen with many ovules
Fruits : berry or capsule
Seeds : many, endospermous

Economic Importance
Many plants belonging to this family are source of food (tomato, brinjal, potato), spice (chilli); medicine (belladonna, ashwagandha); fumigatory (tobacco); ornamentals (petunia).

Lilaceae

Commonly called the ‘Lily family’ is a characteristic representative of monocotyledonous plants. It is distributed world wide.

# Vegetative characters : Perennial herbs with underground bulbs/corms/ rhizomes
Leaves : mostly basal, alternate, linear, exstipulate with parallel venation

# Floral characters -
Inflorescence : solitary / cymose; often umbellate clusters
Flower : bisexual; actinomorphic Perianth tepal six (3+3), often united into tube; valvate aestivation
Androcium : stamen six, (3+3)
Gynoecium : tricarpellary, syncarpous, ovary superior, trilocular with many ovules; axile placentation
Fruit : capsule, rarely berry
Seed : endospermous
Floral Formula : ⊕ P3+3 A3+3 G(3)

# Economic Importance -
Many plants belonging to this family are good ornamentals (tulip, Gloriosa), source of medicine (Aloe), vegetables (Asparagus), and
colchicine (Colchicum autumnale).

 
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