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Posted on 6:59 PM by Wanto and filed under
By Franklin Jones
Though all leaves have the same function, those of the various species differ in shape, thus serving as an important means of identification.
The plant, like all living organisms, also breathes, i.e. it absorbs oxygen and exhales carbon dioxide. This, too, takes place mainly in the leaves.
Leaves may be either simple, with a single blade, which may be lobed, e.g. the hazel, gooseberry and hawthorn, or compound, with three or more blades attached to one stalk, e.g. the bladdernut and common elder.
Simple leaves have blades of various shapes and are described accordingly as acicular, lanceolate, ovate, obovate, orbicular, cordate, rhomboid, etc. Compound leaves may be trifoliate, palmately compound, odd-pinnate or even-pinnate. Trifoliate has three leaflets radiating from the end of the rachis, e.g. the laburnum and common broom. Palmately compound has more than three leaflets radiating from the end of the rachis, e.g.
Thus, for instance, the leaves of Comes mas, Euonymus europaeus, Rhus typhina and Berberis thunbergi turn purplish-red, those of Forsythia suspensa dark violet, Viburnum opulus scarlet, Amelanchier oxalis orange, Rhamnus frangula and Corylus avellana yellow, etc. These autumn hues make just as lovely a picture in parks and in the wild as do the pastel tints of flowering shrubs in spring. Later a corky layer forms between the stalk and the twig, severing the vascular bundles nourishing the leaf.
The leaf then falls to the ground, leaving a pale spot on the twig which is called the leaf scar. In some cases this scar has a characteristic shape and helps in identifying the species in the winter months.
The plant, like all living organisms, also breathes, i.e. it absorbs oxygen and exhales carbon dioxide. This, too, takes place mainly in the leaves.
Leaves may be either simple, with a single blade, which may be lobed, e.g. the hazel, gooseberry and hawthorn, or compound, with three or more blades attached to one stalk, e.g. the bladdernut and common elder.
Simple leaves have blades of various shapes and are described accordingly as acicular, lanceolate, ovate, obovate, orbicular, cordate, rhomboid, etc. Compound leaves may be trifoliate, palmately compound, odd-pinnate or even-pinnate. Trifoliate has three leaflets radiating from the end of the rachis, e.g. the laburnum and common broom. Palmately compound has more than three leaflets radiating from the end of the rachis, e.g.
Thus, for instance, the leaves of Comes mas, Euonymus europaeus, Rhus typhina and Berberis thunbergi turn purplish-red, those of Forsythia suspensa dark violet, Viburnum opulus scarlet, Amelanchier oxalis orange, Rhamnus frangula and Corylus avellana yellow, etc. These autumn hues make just as lovely a picture in parks and in the wild as do the pastel tints of flowering shrubs in spring. Later a corky layer forms between the stalk and the twig, severing the vascular bundles nourishing the leaf.
The leaf then falls to the ground, leaving a pale spot on the twig which is called the leaf scar. In some cases this scar has a characteristic shape and helps in identifying the species in the winter months.
About the Author:
The variety of garden materials present a futher range of garden design in your garden plan, involving color and texture as well as linear design.
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