Classification and Identification of Plants

1. Classification and Identification of Plants College of African Wildlife Management, Mweka Henry Kenneth Njovu 0683 306 750 hnjovu@mwekawildlife.org

2. Outline • Introduction to plants • Plants diversity • Plant taxonomy • Morphological features of plants • Plant identification techniques

3. Introduction • It is difficult to come up with a simpe definition for the word plant. • Plant can however be defined as a multicellular autotrophy (organism capable of making their own food – through the process known as Photosynthesis) in which embryo develops within a female parent

4. Characteristics of Plants • Plants have cuticle- A waxy layer that coats the surface of stems, leaves and other plants parts exposed to the air. The cuticle keeps plants from drying out. • Plant cells have cell walls – a plant cell is surrounded by a rigid cell wall

5. 3.Plants reproduce with spores and sex cells • There are two stages in plant life • Sporophyte – a plant in the spore producing stage of life. Spores can grow directly into an adult plant.

6. 3. Characteristic cont.. 2. Gametophyte – the stage in a plant life where it produces males and females cells • The phenomenon of having two phases in plant life circle is called alteration of generation

7. Importance of plants • Plants are the basis of the food chain • Food and Drinks – Grains, tuber and roots, sugar crops: sugarcane.sugar beet, Protein seeds, oil seeds, fruits, vegetables, coffee, tea, cocoa, beer. • Fibers for making clothes, rope, brooms, brushes and textiles, money etc • Bioindicators – Indicators of environmental stress/disturbances • Biogeoindicators- Plant are used as indicators in ground water surveys, geologic mapping, and mineral prospecting.There are three commonly applied methods in geobotanical prospecting: (1) mapping of indicator plants, (2) assessing plant appearance and physiology, and (3) chemical testing of plants known to accumulate specific elements.

8. Importance of plants cont... • Plants are responsible for the presence of oxygen, a gas needed for most organisms on earth. • Plants have and still protect us from global warming by absorbing the excesscarbondioxide gas. • Plants provide habitat for other living organisms • They provideoutdoor recreational facility • Plants provide jobs. If you go through all the points above, you will see how plants provide job opportunities.Currently 50% of world workers engage in cultivation of plants.

9. Major threats facing Plants • Deforestation- Mining activities, firewood, building materials, charcoal and opening up of farms. • Alien Invasive species – secong biggest threat • Over exploitation – legal and illegal exploitation of forests through lumdering etc • Diseases and Parasites • Climate Change • Environmental pollution – acid rain and chemicals from industries e.g Lake Tigite

10. Plants Diversity • Bryophyte – Are the first period of plants in evolution believed to evolve from Charophytes – their aquatic algal ancestors. • They are also known as lower plants or Non vascular plants because they lack lignin hardened vascular tissues instead they use diffusion and osmosis to absorb food. • Bryophyta (Moss)- have leaves growing from the stem and in many species, you will see solid-stalked spores capsure growing from leafy part of plant. • Hepaticophyta (Liverworts) and Anthocerophyta (Honeyworts) are stalkless. Liverworts looks like liver lobe and Hornworta are not leafy. • Many of these plants are are soft and looking green covering on damp banks, trees and logs that are shaded

11. Bryophytes are Non-vascular Plants: • have no pipes to transport water (Xylem) and nutrients (Phloem) • depend on diffusion and osmosis to move material from one part of the plant to another • They have to be small: Bryophytes (mosses, liverworts) and Pteridophytes (Ferns). • They are often referred to as Lower Plants

12. Pteridophyte e.g ferns • They are the second period of plant evolution. They are marked by the development of vascular tissues (xylem and phloem) with lignin hardened tissues. • They lack seeds and flowers but have stems, leaves and roots like other vacular plants. Their reproduction is by spores.

13. Gymnosperm – Cone bearing plants e.g. Pinus spp • The third period of plant group in evolution. They marked the origin of seeds. • Gymnosperm in greek words mean gymno=naked and sperma= seed. • Thus they are reffered to as naked seed as their seeds are not enclosed within a fruit as in flowering plants. • The seed consists of an embryo packed along with a food store within a protective coat.

14. Angiosperms - Flowering plantse.g. Hibiscus • The forth period of plant group in evolution or the modern plant group They marked the origin of enclosed seeds. • The seeds (a mature and fertilized ovule) of angiosperm is enclosed in fruits which are defined as a mature ovary.

15. Vascular Plants • Have tissues (Xylem and Phloem) that deliver needed materials throughout a plant - called vascular tissues. • Can be almost any size. • Are divided into Pteridopytes, gymnospermsand angiosperms • They are also referred to as Higher Plants

16. Questions • Without plants, the world is said to collapse. Discuss (20 Marks). • Distinguish vascular plants from non vascular plants (4 Marks). • Differentiate lower plants from higher plants (4 Marks). • Write short notes on Bryophytes (5 Marks). • Distinguish pteridopytes from angiosperms (4 Marks). • Why do you think modern plants are classied under Plantae Kingdom

17. Plants Taxonomy • Plants taxonomy is the naming, describing and classifying of plants. • The goal of plant taxonomy is to recognize, and properly explain the variation of plants and to systematically organize this information. • Plant Taxonomy is sometimes refered to as systematic botany or plant systematic and is a fundamental part of the study of biodiversity. • Plant taxonomy is the center of a web of inter-related areas of botany. Taxonomists use informationabout structure, chemical composition, physiology, ecology, genetics,evolution,geographical distribution and many other forms of data in interpreting relationships among plants.

18. Taxonomy cont.. • The key role of taxonomists is the organization of diverse forms of information about plants. Taxonomists provide information to other workers in other areas of Biology. • The most common question to taxonomists is ”what kind of plant is this”. The answer to this question is often the key to finding additional information.

19. Basic Activities in Taxonomy • 1) Identifying 2) Cataloging and 3) Classifying • Nothing new here! You have been doing this from your childhood – Spoons (Teaspoon, Tablespoon), knives, forks- Silverware. • Recognizing that a particular object is a member of a group and associating it with the names of that group – Identification • Organization of objects into groups and ranking (species, genus, family) – Classification • Although you might have not seen before the particular knives, forks or spoons illustrated. But you can recognize them (identify them as something you had previously cataloged) and you can associate them with appropriate code – words.

20. 1. Identification • Identification of plants can take place in several ways. You might identify plants in the same way that you identified teaspoons, butter knives and other familiar objects for which you already have mental concept. • But what if you have never encountered the plant before? Even the most highly trained botanists can recognize on site only a small fraction of plants. • For determining the names of unknown plants, both you and the specialists need dependable techniques.

21. Techniques • Make use of expert knowledge • Use comparison methods • Use of a taxonomic key. The process of keying is an artificial method of locating information by emphasizing similarities and differences among plants. In all the three techniques always learn to recognize major groups of plants or major plant families (by learning the features of the families and developing mental concepts for them) is a major step in plant identification.

22. 2. Cataloging • Cataloging involves three (3) steps: - Naming, Describing and Recording. • Naming is essential to communication. We assign names to plants, people and to everythingelse around us. Names are nouns of our language; they are codes that stands for objects or concepts, processes. • The coding process for assigning names to plants results in a nomenclature of system of names. • Describing is our means of assembling and communicating information about attributes/characteristics of the objects or concepts to which we have assigned names. • Recording – Information about objects that have been named and described must be recorded in some fashion if it is to be used.

23. 3. Classification • The basic processes of classification are grouping and ranking. • Grouping involves the sorting of objects into groups that have some features in common. • Ranking is the organization of the groups into a nested hierarchy of small groups within progressively more inclusive groups. E.g Kingdom, Division (Phylum in Animalia Kingdom), Class (subclass), Order, Family - Subfamily)– Tribe, Genus – subgenus-Section, Species – subspecies-Variety-Form • Each group that is recognized in the classification hierarchy is called a taxon (taxa).

24. Skills a taxonomist need to acquire • The recognition of a fairly large number of plants • Knowledge of techniques used to identify any plant which is unknown.

25. Why should you study taxonomy • Some students aspire to taxonomy as a career. • Some study taxonomy because they want to be users of the knowledge and not practitioners. E.g. Those working in agriculture, forestey, biology, environment and management. • Some students just take taxonomy class because they are interested in the subject. Some individuals may be employed in a position that has no direct connection with plants but be an anthusiastic and knowledgable amateur botanist. Many members of organizations dedicated to conservation and enjoyment of natural resources have benefited from trainingin taxonomy. Your experiences in plant taxonomy will undoubtedly change the way you observe plantsaround you.

26. Botanical Nomenclature • Nomenclature is the giving and using of names. Names are nouns we use to represent the objects and phenomenon around us. • Communication is aided by names that are readily understood by those hearing or reading the words. • Names allow us to communicate without reporting to lengthy descriptions. • For example we can say “Cow” to represent the large four-legged animated hairy object with a large sack underneath that gives us milk.

27. Types of names • There are two types of names; common names and scientific names. • Common names are the older and they are created by people doing the everyday living of life. • These are words in the layman language and thus are easy to understand and use. • Although common names are widely used, there are some disadvantages. • Common names are developed in the language of a given people and may not be useful to people with a different language. • Wide ranging plants often have several different common names, some of them are widely used and others unique to a given locality or language. • One plant can have more that one different common names in one locality, this multiplicity of common names can cause confusion in communication

28. Common names.. • Some two or more kinds of plants share the same common name. In such scenario common names may be barrier to communication between individuals using the name for different genera. • People develop words only for those objects they see and use. If the plant is inconspicuous of rare, it may not have a name. • Sometimes common names represent what botanist would consider to be a single species and sometimes they represent a genus or a large group. • Common names have a place in everyday life but can not be used in serious scientific studies or even in horticultural activities. Take an example of what we call Christmas tree. • Generally, common names have limited use, confusing, misleading, inaccurate and bring barrier to communication

29. Scientific Names • Scientific names evolved out of the study and reporting of plants in books during 13th to 18th century. • This was a period when Europeans were explored the world beyond their continent and many unfamiliar plants and animals were being seen for the first time. • Because the language of learned men of this period was Latin, names of plants were written in Latin. This use of Latin has been passed on in the formal naming of plants, this is happening even today regardless of their original derivation. • Initially, naming varied from one individual to another, Species name consisted of a generic name followed by one or more Latin modifiers. This system produced long and cumbersome names which are now known as polynomials. • Such names carried two roles. It was a name and it was also a diagnosis (a set of distinguishing features) of a plant.

30. Scientific names cont.. • The Great Swedish Naturalist Carolus Linnaeus (1707-1778) started the work on establishing standard procedures for naming plants. • Linneaus formulated underlying principles for botanical nomenclature in the 1730s and in 1751 he published a book called PhilosophiaBotanicain which he set forth the principles of nomenclature he had adopted. • These principles served as a sound foundation for later botanists. • Today we have a set of formalized rules of naming plants called them International Code of Botanical Nomenclature(ICBN).