Q.Give a semi-technical description of a typical flowering plant.

Purpose of the Semi-Technical Description

When a taxonomist examines a flowering plant for identification or record-keeping, the description is not written as a casual narrative but follows a fixed, standard sequence of characters. This ordered format is called a semi-technical description: "semi-technical" because it uses precise botanical terminology for each character (making it more exact than a plain descriptive account) while still being written out in readable phrases and sentences rather than reduced entirely to symbols and abbreviations (which would make it a fully technical or telegraphic description). Following a fixed sequence every time makes descriptions of different plants directly comparable to one another, and ensures that no important character is accidentally left out.

Habit and Habitat

The description opens by recording the plant's habit — whether it is an herb, shrub, tree, or climber — and its habitat, meaning the kind of environment in which it typically grows (for example, common wayside places, cultivated fields, or a particular climatic zone). This gives an immediate, general picture of the plant before any detailed characters are considered.

Vegetative Characters

Next, the vegetative parts are described in a fixed order: root, stem, and leaf. The root system is noted as tap root or adventitious/fibrous, and any special features such as root nodules are mentioned. The stem is described for its nature (herbaceous or woody), form (erect, climbing, or twining), and any special modifications. The leaf is described for its type (simple or compound), arrangement (alternate, opposite, or whorled — phyllotaxy), venation (reticulate or parallel), and the presence or absence of stipules. These vegetative characters, although less emphasized in identification than floral characters, still provide useful supporting evidence for placing a plant in its correct family, and unusual vegetative features (such as the geocarpic fruiting habit seen in a few plants, where the fruit matures underground after the flower stalk pushes it into the soil, as in groundnut) are noted here as well.

Floral Characters

After the vegetative description, the account moves systematically through the floral characters, again in a fixed sequence: inflorescence (the arrangement of flowers on the plant, such as raceme, cyme, or solitary flower), flower (its symmetry — actinomorphic or zygomorphic — and its sexuality — bisexual or unisexual), and then whorl by whorl: calyx (number and fusion of sepals), corolla (number, fusion, and shape of petals), androecium (number of stamens, their fusion or arrangement, and the structure of the anthers), and gynoecium (number of carpels, their fusion, the position of the ovary relative to other floral parts, and the type of placentation). Finally, the fruit type is noted, since fruit character often confirms the family assignment made from the flower.

Floral Diagram and Floral Formula

The semi-technical description is conventionally closed by two condensed, symbolic summaries of everything just described: the floral diagram, a schematic cross-sectional drawing showing the number and arrangement of parts in each whorl relative to the mother axis and the subtending bract, and the floral formula, a shorthand notation using letters, numbers, and symbols to represent the same information in a single compact line. Presenting both at the end of the description allows a reader to grasp, at a glance, everything that the longer prose description has just stated in detail, and it is this fixed habit → vegetative characters → floral characters → floral diagram → floral formula sequence that is followed for each of the three families treated later in this chapter.