Morphology of plants

By the end of this lesson you will be able to: • Identify the parts of a flower. • Describe how the whorls of floral parts are related to leaves emerging from nodes on a stem. • Describe ways in which flower structure affects pollination. General introduction to flower parts The angiosperm flower is built upon a structural foundation consisting of a compressed stem with four nodes and three internodes. For a visual image of these compressed nodes, imagine pushing down on a telescoping radio antenna so that the antenna sections slide down into each other. At the very top of the fully compressed antenna you’ll still see the tips of each of the sections of the antenna, and this resembles the highly compressed nodes and internodes of a stem. The region of the stem containing these four compressed nodes is called the receptacle. We have seen other examples of compressed stems with very short internodes, including the basal plate of the onion. In each of these cases we find leaves attached to these tightly compressed nodes. In the onion, the leaves are modified for water and nutrient storage as bulb scales. In the dandelion, the leaves are unmodified, but are arranged in a low-growing rosette. The flower is another example of a very compact stem with four nodes and three internodes. The leaves on this stem are highly modified to serve a reproductive function. They are so highly modified that, except for the structures at the fourth node, the parts don’t resemble leaves at all. M...

By the end of this section you will be able to: • List the seven levels of the plant classification system. • Recognize the taxonomic diversity of common foods in your diet. • Summarize the contribution of Linneaus to binomial nomenclature. • Understand how the two-part scientific naming system works and its applications. Plant taxonomy Here are some introductory definitions: Taxonomy (or systematics): The science of classifying organisms. Classification: A grouping of plants according to shared qualities or characteristics. Plant taxonomy: A hierarchical classification system based on morphological (see below) and phylogenetic (see below) similarities among plants. Nomenclature: A formal system of names attached to taxonomic groupings. Hierarchy: A system of grouping in which each classification is a subset of a superior grouping, and may contain subordinate categories. As an example: The landmass of the United States (used here as the highest or most inclusive level of classification) is partitioned into states (a middle level of classification). States, in turn, are partitioned into counties (the lowest level in this hierarchy). Counties are subsets of states, which are in turn subsets of the nation. This hierarchical type of grouping system is used in plant taxonomy. Morphology: The appearance (shape and structure) of a plant. Plant taxonomy is a hierarchy primarily based on grouping together plants that exhibit structural (phenotypic) similarities. Phylogeny: Ancestra...

With an awareness of the many forms that plants, flowers, and leaves come in, a hike in the woods or a stroll through a garden can transform from a blur of green to a diverse exhibit of morphology. With attention to morphology, along with an understanding of binomial nomenclature and the evolutionary relationships that plant names imply, that hike or stroll can also become a climb through the botanical family tree! The more you practice looking at nature through this lens, the easier and easier it will become to identify unknown plant species. In this post, we’d like to expand on the topic of plant morphology and why it matters to the plant enthusiast. We’ll look at various ways to describe leaves and get specific with an example from the herbal world to see morphology in action. Morphology? While this term may sound intimidating, it’s actually very easy to understand. Morphology is the study of the form of a plant or plant part. Morphology is an important subject for herbalists to know, especially if you ever find yourself writing an herbal monograph, hosting a plant walk, writing an article on plant identification, or engaged in any other activity where morphology and descriptive language is needed. Getting To Know Plants On A More Intimate Level If we are are lucky, we can get to know deeply the plants of one region in our lifetime. However, if we learn to recognize patterns in plant morphology, even if we are new to a geographical region, we can have an easier time ide...

\( \newcommand\) How to distinguish compound leaves (left) from branches (right). of secondary chemicals. Features of a leaf (i.e., characters help to distinguish it) include having a bud in the axil, not growing by apex, not producing new leaves or shoots, and having hierarchal morphology (see below). Morphology of the Leaf Morphologymeans external, well visible structural features whereas anatomy needs tools like a scalpel and/or microscope to study needs tools like a microscope and/or scalpel. Leaves are very important in plant morphology. The ability to describe the leaf is a must even for novices in botany. In all, plants are fractal organisms, like Sierpinski triange (Figure \(\PageIndex\) The simple classification of leaf venation. 1. General characters (leaf as a whole): (a) stipules (present / absent, deciduous / not, how many, size, shape); (b) base (sheath / no sheath, ocrea / no ocrea) 2. First level of hierarchy: repetitive characters: (a) symmetry (symmetrical / asymmetrical); (b)shape; (c) dissection; (d) petiole (presence and length) 3. Second level of hierarchy 4. Third level of hierarchy, and so on 5. Terminal characters (leaflets): (a) base of leaf blade (rounded, truncate, cuneate, cordate); (b) apex (rounded, mucronate, acute, obtuse, acuminate); (c) margin (whole, dentate, serrate, double serrate, crenate ); (d) surfaces (color, hairs etc.); (e) venation (apo-, hypho-, acro-, ptero-, actinodromous) Heterophylly h refers to a plant having more than one...

At the species level, plants can respond to climate changes by changing their leaf traits; however, there is scant information regarding the responses of morphological, physiological and anatomical traits of plant functional types (PFTs) to aridity. Herein, the leaf traits of five PFTs representing 17 plant species in temperate grasslands were examined along a large-scale aridity gradient in northeastern China. The results show that leaf thickness in shrubs, perennial grasses and forbs increased with heightened aridity. Trees increased soluble sugar content, but shrubs, perennials and annual grasses enhanced proline accumulation due to increasing aridity. Moreover, vessel diameter and stomatal index in shrubs and perennial grasses decreased with increasing aridity, but stomatal density and vascular diameter of five PFTs were not correlated with water availability. In conclusion, divergences in adaptive strategies to aridity among these PFTs in temperate grasslands were likely caused by differences in their utilization of water resources, which have different temporal and spatial distribution patterns. Leaf traits of shrubs and perennial grasses had the largest responses to variability of aridity through regulation of morphological, physiological and anatomical traits, which was followed by perennial forbs. Trees and annual grasses endured aridity only by adjusting leaf physiological processes. At global and regional scales, the increase in aridity poses the most important ...

This manual is written with the assumption that most readers have either taken a botany course or had practical experience working with plants or botanical materials, so that they have some familiarity with the basic structure of a plant. Space limitations require that a review of plant morphology be kept to the barest minimum. If a more detailed review is needed, any textbook of botany or plant biology will suffice (Raven, Evert & Eichhorn’s Biology of Plants is highly recommended). Technical vocabulary is kept to a minimum in this text; that which cannot be avoided is defined in the glossary. A more complete reference is Harris & Harris’ Plant Identification Terminology. Within those limitations, let us take a few paragraphs to review the structure of typical flowering plants. Flowering plants, like other “advanced” vascular plants, have complex forms that are constructed from just a few basic types of plant organ. An average plant has a root or roots, a stem, leaves, and flowers, which produce fruits and seeds. There are of course variations; for example, plants such as dandelions have all leaves borne at ground level, with no stem, while others, such as many cacti, have no leaves. In some plants, the stems become thick and woody trunks, branches or twigs. These organs are constructed in turn from a limited number of basic tissue types. Many of the soft tissues of a plant, such as the photosynthetic inner parts of a leaf, the ground tissue of a stem, or the fleshy corte...