Chapter 6. Plant Morphology
Plant morphology is the study of the external structure or form of plants. The concept was put in circulation by the author Johann Wolfgang von Goethe, in the early 1800s. You have already covered important aspects of plant morphology in the previous chapters on plant organs (leaves, stems, roots), flowers, and fruits. Those chapters emphasized both plant anatomy (the internal structure) and plant morphology (the external form) of specific parts or organs. Here, we will be concerned especially with the various growth forms that plants take and how such morphologies contribute to the success of each species.
Simple plant forms
The forms taken by simpler "plants" (e.g., algae) will be considered in greater detail in Section II of The Guide. However, lichens offer a good general introduction to basic plant forms in a group whose members are sometimes informally classified on the basis of morphology.
- Read Lichens (You need not follow links except to clarify unfamiliar terms)
Imagine an early earth, with most life in the oceans, but the beginnings of terrestrial life represented by primitive photoautotrophic organisms spread over rocky surfaces. In the seas, the autotrophs would be floating forms and encrusting slimes, or calcareous rich crusts.
When we think about the evolution of more complex forms, even within such groups that today appear rather primitive such as the multicellular algae, we need to consider what forces were operating on the mechanism of natural selection to drive evolution in certain directions. We must also always be mindful of realistic limitations.
When you previously read the article on algae, you may recall the following description of life forms of these simple "plants": Most algae are unicellular, flagellates or amoeboids, but colonial and non-motile forms have developed independently among several of the algal groups. The more common organizational levels beyond unicellular forms are:
- Colonial – small, regular groups of (usually) motile cells
- Capsoid – individual non-motile cells embedded in a common mucilage
- Coccoid – individual non-motile cells with adherent cell walls
- Palmelloid – non-motile cells embedded in common mucilage
- Filamentous – a string of non-motile cells connected on end together and sometimes branching
- Parenchymatous – cells forming a thallus with partial differentiation of tissues
Complex plant forms
- Read Trees (You need follow links only to clarify unfamiliar terms)
- Read Shrubs (You need follow links only to clarify unfamiliar terms)
- Online Image Collection of the Botanical Society of America
From the earliest times itself plants have been classified as herbs, shrubs and or trees. Reference-Morphology of Plants. By S.R. Mishra, Published by Discovery Publishing House, 2004 ISBN 817141821X, 9788171418213
Herbs read Herbs at Wikipedia
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