SCHEME FOR THE COMPLETE DESCRIPTION OF AN ANGIOSPERMIC PLANT

One of the important purposes of the study of External Morphology is to be able to describe a plant completely and correctly.

Without such a description it is not possible to identify a plant and to ascertain its place in the plant kingdom, i.e. to assign it to its family, genus, species etc.

To describe a plant a student should follow the scheme given below. It will be seen that to make his description accurate, the student will have to exercise all his knowledge of Morphology.

Habitat: Locality with latitude, longitude and altitude. The natural climatic and edaphic environment of the plant, namely aquatic or terrestrial, type of soil or rock (sandy, calcareous, etc.), bright sunshine, shade, desert conditions, etc.

Habit: Epiphyte, parasite, etc.; herb, shrub, tree, climber; annual, biennial, perennial; succulent, woody, deciduous, evergreen; size, etc., general characters of the whole plant.

Root: Tap, adventitious, or any special type etc.

Stem: Characters not included under habit.

 Branching.

 Surface of stem – glabrous, hairy, etc.

Colour of stem.

Shape – round, square, ribbed, etc.

Hollow or solid, jointed or not.

Any special modification – phylloclade, etc.

Leaf:   Phyllotaxy.

Insertion – radical or cauline, petiolate or sessile, peltate, etc.

Simple or compound – type of compound.

Leaf base – stipulate or exstipulate, kind of stipule, any                                            speciality.

Petiole – any speciality.

Leaf lamina – shape, venation, margin, incision, apex, base, surface, texture, glands, colour, odour and taste.

Modifications and specialities (ligule, stipel, heterophylly, etc.)

Inflorescence: Type – racemose, cymose, etc.

Flower:

General:   Bracteate or ebracteate – type of bract.

Bracteole – if any.

Sessile or pedicellate.

Complete or incomplete – dichlamydeous, monochlamydeous, achlamydeous, etc.

Bisexual or unisexual – monoecious, dioecious, etc.

Symmetry – regular, zygomorphic or assymetrical.

Floral phyllotaxy – cyclic, spiral, hemicyclic.

Insertion – hypogynous, perigynous, epigynous.

Erect, pendulous, etc.

Size.

Any speciality – disc, nectary, etc.

Thalamus: Any speciality not included under flower.

Calyx: Cohesion – polysepalous or gamosepalous.

Number of sepals or lobes.

Superior or inferior.

Aestivation.

Calyx shape – sepal shape.

Size (of calyx and sepals).

Colour.

Duration – caduceus, deciduous, persistent.

Any speciality (modification, appendage, etc.)

Corolla: Cohesion – polysepalous or gamosepalous.

Adhesion.

Number of petals or lobes.

Superior, inferior.

Aestivation.

Corolla shape (regular or irregular) – petal shape.

Size – corolla and petals.

Colour, duration, texture, scent.

Perianth: (When calyx and corolla cannot be distinguished).

Sepaloid or petaloid.

Other characters as in calyx and corolla.

Androecium: cohesion – in filament, in anther, in both.

Number – fertile and sterile ones as also separate whorls separately counted.

Adhesion – with corolla or gynoecium.

Superior or inferior.

Filament – any outgrowth, sessile or not, length.

Anther – attachment of filament, dehiscence, introrse or extrorse, number of pollen sacs, appendages.

Pollen- powdery, etc; appearance; pollinia.

Colour.

Speciality – didynamous, etc.; obdiplostemonous, etc.; exserted or inserted; nectaries, etc.

Gynoecium: Cohesion – apocarpous, syncarpous, etc.

Number.

Adhesion – with Androecium.

Ovary – shape, number of loculii, placentation, superior or inferior.

Style – number; free or united; terminal, lateral, gynobasic, etc.; shape; size; colour; any peculiarity.

Stigma – number; sessile or not; shape – simple, lobed, branched, etc.; smooth or papillose; any speciality.

Ovule: number; number in each loculus; ascending, horizontal, etc., anatropous, campylotropous, etc.

Any speciality in the gynoecium.

Floral Diagram & Floral Formula.

Pollination: Type if observed.

Fruit: True or false; dry or fleshy; dehiscent or indehiscent.

Type of fruit, manner of dehiscence (if dehiscent).

Size.

Any speciality (edible, poisonous, etc.; which part edible).

Seeds: Number of seeds in fruit.

Morphology – perisperm, endosperm (nature of food reserve), embryo.

Size and shape.

Any speciality (aril, etc.)

Manner of germination.

Method of dispersal.

·       Any description should be accompanied by neat and representative labelled sketches/diagrams/figures.