In this book 100 species selected on the basis of wide consultation are grouped as a) Broad leaved trees and shrubs, b) Mangrove trees and shrubs, c) Palm trees, d) Pandanus trees and shrubs and e) Narrow leaved tree - Casuarina. The fact sheets for each species include the following information:
Common name(s) and Dhivehi name(s)
Ecology, propagation and management.
Each species is illustrated with a combination of colour photos and drawings showing habit, bark, leaf structure, inflorescence, flowers, fruits and other characteristic features useful in identification. Under the heading `uses', information on how the Maldivian community utilize different parts of the tree or shrub is given together with details relating to potential commercial use. Information on the soil types in which particular trees and shrubs flourish and their tolerance to various environmental conditions such as salt spray, soil salinity, drought and wind, etc., is also given. Trees and shrubs useful in creating coastal bioshield are indicated and major methods of propagation are given for each species along with management information. References providing additional information on ecology, propagation and management of different species are given at the end of the book.
To assist identification of featured trees and shrubs, plant physical attributes have been described with the minimum usage of technical terms. Some traditional botanical terms that may not be familiar to users have, however, been included and are explained here with illustrations provided to assist simple identification.
Simple leaf: A leaf with a single leaf blade is called a simple leaf or a solitary leaf. The leaf blade may be entire or dissected into lobes or divided pinnately or palmately as shown below.
Entire: simple leaf that has no incisions
Pinnately lobed: simple leaf that has many lobes that are arranged on either side on the midrib
Palmately lobed: simple leaf that is divided into three or more distinct lobes, like the fingers of a hand
Bi-lobed: simple leaf that is divided into two lobes
Compound leaf: A compound leaf is a leaf where the incisions are such that the leaf is cut into distinct separate blades called leaflets. All the leaflets of a compound leaf are oriented in the same plane. When the compound leaf falls from the tree, it falls as a unit. In a compound leaf, the midrib is the rachis on which the leaflets are borne.
Pinnately compound leaf: leaf that has many leaflets, which are arranged in pairs on either side the rachis (looks like a feather)
Paripinnately compound leaf: pinnately compound leaf with no terminal leaflet
Imparipinnately compound leaf: pinnately compound leaf with a single terminal leaflet
Bipinnately compound: compound leaf that is twice pinnate with compound leaflets arranged on both sides of a central stalk
Palmately compound: compound leaf with many leaflets diverge from a common point (like the fingers of a hand)
Trifoliate: compound leaf that has only three leaflets, one at the tip and two below
Leaf shape refers to the outline of the leaf blade. The following are the main types of leaf shapes:
Linear: leaf that is long and narrow, with parallel or nearly parallel sides. Length of the leaf is generally more than ten times the width.
Lanceolate: leaf that looks like a lance, very long but narrow blade, widening about the base and tapering at the top, broadest point below the middle
Oblanceolate: leaf that is shaped like an inverted lance, broader at the top end than at the middle and tapering towards the base
Ovate: leaf that looks like a hen's egg, broadest point of the leaf is below the middle
Obovate: leaf that has an inverted egg shape
Elliptic: leaf that is longer than wide, narrow to round ends and widest at or about the middle. Leaf length is at least two times the width
Oblong: leaf that is longer than broader with the sides more or less parallel for most of the length of the leaf. The length is usually less than ten times the width
Cordate: leaf that looks like a heart, having two equal more or less round lobes at the base
Peltate: leaf like a shield with a flat leaf blade and a central leaf stalk
This refers to tip of the leaves. The following are some of the major types of leaf tips:
Acute: sharply pointed tip
Acuminate: tapering to a long point
Apiculate: tip with a short, sharp, but not stiff, point
Obtuse: blunt, rounded tip
Emarginate: tip with a swollen notch at the apex
Mucronate: terminating abruptly by a short sharp point at the apex
The following are the common types of bases noticed in many of the plants:
Attenuate: tapering gradually
Acute: pointed, forming less than a right angle
Obtuse: blunt, usually more than a right angle
Truncate: appearing as if the base is cut off, nearly straight across
Auriculate: having an ear shaped part at the base
The following are the common types of margins found in leaves.
Entire: even and unbroken margin
Sinuate: margin with deep and rounded incisions
Serrate: margin toothed like a saw, with fine teeth pointing outwards
Undulate: margin which is wavy
Crenate: margin with shallowly round teethed
Alternate: only one leaf is present at a node and leaves are on the same plane
Opposite: two leaves inserted opposite to each other on the stem
Spiral: leaves arranged singly but they arise all around the stem facing different planes
Whorled: three or more leaves radiating from a single point facing different planes
Flowers are the most remarkable feature of angiosperms (flowering plants). They show striking variations in colour, shape and smell and therefore are considered as an important external feature of a plant that can be used for the identification of a plant species. The following is the cross section of a flower showing the different parts (Fig. 2):
Fig. 2. Longitudinal section of a flower
An inflorescence is a group or cluster of flowers on a plant. It is otherwise called a flower head or flower cluster. The stalk of the inflorescence is called the peduncle and the stalk of an individual flower is called the pedicle. Flowers arise in the axils of reduced leaf-like structures called bracts and a cluster of bracts is known as involucre.
An inflorescence is single when all the flowers are gathered in the same single pattern and it is called compound when a complex pattern is formed from other single patterns.
Main types of single inflorescences are as follows:
Raceme: a simple elongated inflorescence with stalked flowers; length of the stalk is equal in all the flowers
Spike: it is similar to raceme but flowers attached directly to the peduncle
Spadix: a thick fleshy spike, surrounded or subtended by a spathe (a large, often showy bract); flowers usually unisexual and minute
Corymb: it is similar to raceme but length of the stalk is unequal. It is flat topped with the oldest flower at the end of the main axis
Cyme: it is similar to corymb and flat topped with the youngest flower at the end of the main axis
Umbel: flowers are with equal stalk length and they arise from a single point from the top of the peduncle
The following are the main types of compound inflorescences:
Panicle: it is formed by several racemes clustered together
Compound umbel: it is formed by several umbels clustered together
Fruits are the seed-bearing organ of a plant, which display a wide range in size, shape and colour. It is another external feature that is used for identifying plants.
Pod: long dry fruit consisting of a seedcase, which splits open to release its seeds
Drupe: fleshy fruit having a single hard stone that encloses a seed
Berry: small, juicy fruit having the whole wall fleshy
Capsule: dry fruit that develops from two or more carpels (female reproductive unit of a flower comprising stigma, style and ovary)