Plant Identification

To properly identify a plant, the whole plant has to be carefully observed. The physical form and external structure have to be studied to see what categories the plant fits into. These are the features that need to be observed.

Habit (form)

Herb: Plants that have non-woody stems. Herbs can be annuals or perennials

Shrub: Woody plants that are less than 6m tall and have multiple stems. Shrubs are perennials.

Tree: Perennial woody plants with an elongated trunk with leafy branches at the top.

Climber: Plants with stems that are unable to stand erect, and use trees and other objects to climb up. There are herbaceous as well as woody climbers (lianas)

Leaf type

Simple

A leaf that has an undivided blade. The leaf may be lobed but does not form distinct leaflets.

Simple leaf

Compound

The leaf blade is separated into separate leaflets. There are several ways in which the leaflets may be arranged on the rachis.

Pinnate (odd): Leaflets are attached along the rachis; there is a terminal leaflet and therefore an odd number of leaflets.

Imparipinnate leaf

Pinnate (even): Leaflets are attached along the rachis; there is no terminal leaflet and therefore an even number of leaflets.

Paripinnate leaf

- Bipinnate: Leaflets that are further subdivided in a unipinnate arrangement.

Bipinnate leaf

- Tripinnate: Leaflets that are further subdivided in a bipinnate arrangement.

Tripinnate

Trifoliate: A compound leaf made up of three leaflets.

Trifoliate leaf

Palmate/Digitate: A type of compound leaf in which the leaflets all originate from the same point, like the fingers from the palm of the hand.|

Palmate leaf

A way to distinguish simple leaves from compound leaves is to check for axillary buds. Only simple leaves would have an axillary bud. Pinnate leaves will not have them.

Leaf arrangement

Alternate: One leaf attached at a node, arranged alternately on the stem.

Opposite: A pair of leaves attached at a node, arranged oppositely.

Opposite

Whorled: Three or more leaves attached at a node, in a radial manner.

Whorled

Basal Rosette: Some plants keep their leaves in a tight rosette close to the ground, where the leaves all seem to radiate from a common point. This may be one stage in the life of the plant or it may spend its whole life in that form.