Sunday, July 26, 2020

Morphology of Flowering Plants - Notes | Class 11 | Part 6: Plant families

5. MORPHOLOGY OF FLOWERING PLANTS


SEMI-TECHNICAL DESCRIPTION OF A TYPICAL FLOWERING PLANT

- The plant is described beginning with its habit, vegetative characters and then floral characters.

-    Then a floral diagram and a floral formula are presented.

-    Floral formula is represented by some symbols. They are


-  Fusion is indicated by enclosing the figure within bracket and adhesion by a line drawn above the symbols of the floral parts.

-  Floral formula also shows cohesion and adhesion within parts of whorls and in between whorls.

-   A floral diagram gives information about the number of parts of a flower, their arrangement and relation.

Floral diagram of mustard plant (Family: Brassicaceae)

Floral formula:  K2+2 C4 A2+4 G(2)


SOME IMPORTANT FAMILIES

1. Fabaceae

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

Vegetative Characters:


o  Trees, shrubs, herbs; root with root nodules.

o  Stem: Erect or climber.

o  Leaves: Alternate, pinnately compound or simple; leaf base, pulvinate; stipulate; venation reticulate.

Floral characters:


o  Inflorescence: Racemose.

o  Flower: Bisexual, zygomorphic.

o  Calyx: Sepals five, gamosepalous; valvate/imbricate aestivation.

o  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.

o  Androecium: Ten, diadelphous, anther dithecous.

o  Gynoecium: Ovary superior, mono carpellary, unilocular with many ovules, style single.

o  Fruit: Legume; seed: one to many, non-endospermic.

o  Floral Formula: %K(5) C1+2+(2) A(9)+1 G1

Economic importance:


o  Pulses: E.g. gram, arhar, sem, moong, soyabean.

o  Edible oil: E.g. soyabean, groundnut.

o  Dye: E.g. Indigofera.

o  Fibres: E.g. sun hemp.

o  Fodder: E.g. Sesbania, Trifolium.

o  Ornamentals: E.g. lupin, sweet pea.

o  Medicine: E.g. muliathi.

2. Solanaceae (Potato family)

It is a large family. It is widely distributed in tropics, subtropics and even temperate zones.


Vegetative Characters:


o  Plants mostly herbs, shrubs and small trees.

o  Stem: Herbaceous rarely woody, aerial; erect, cylindrical, branched, solid or hollow, hairy or glabrous, underground stem in potato (Solanum tuberosum).

o  Leaves: Alternate, simple, rarely pinnately compound, exstipulate; venation reticulate.


Floral Characters:


o  Inflorescence: Solitary, axillary or cymose as in Solanum.

o  Flower: Bisexual, actinomorphic.

o  Calyx: Sepals five, united, persistent, valvate aestivation.

o  Corolla: Petals five, united; valvate aestivation.

o  Androecium: Stamens five, epipetalous.

o  Gynoecium: Bicarpellary obligately placed, syncarpous; ovary superior, bilocular, placenta swollen with many ovules, axile.

o  Fruits: Berry or capsule.

o  Seeds: Many, endospermous.

o  Floral Formula:

Economic Importance:


o  Food: E.g. tomato, brinjal, potato.

o  Spice: E.g. chilli.

o  Medicine: E.g. belladonna, ashwagandha.

o  Fumigatory: E.g. tobacco.

o  Ornamentals: E.g. petunia.

3. Lilaceae (Lily family)

A characteristic representative of monocotyledonous plants. It is distributed worldwide.


Vegetative characters:


o   Perennial herbs with underground bulbs/corms/ rhizomes.

o   Leaves mostly basal, alternate, linear, exstipulate with parallel venation.

 Floral characters:


o   Inflorescence: Solitary / cymose; often umbellate clusters.

o   Flower: Bisexual; actinomorphic.

o   Perianth tepal six (3+3), often united into tube; valvate aestivation.

o   Androecium: Stamen six, (3+3).

o Gynoecium: Tricarpellary, syncarpous, ovary superior, trilocular with many ovules; axile placentation.

o   Fruit: Capsule, rarely berry.

o   Seed: Endospermous.

o   Floral Formula: 

Economic Importance:


o   Ornamentals: E.g. tulip, Gloriosa.

o   Medicine: E.g. Aloe.

o   Vegetables: E.g. Asparagus.

o   Colchicines: E.g. Colchicum autumnale.


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