1. Chapter 3. Naming and Organizing Plants

2. Taxonomy The process of giving names to newly discovered organisms
The discoverer’s name follows the genus and species name
Rules for naming plants follow the International Code for Botanical Nomenclature
Plants named by Linneaus are followed by ‘L’

3. Agaricus xanthoderma
Poisonous mushrooms look very similar to their edible relative, which can be member to the same genus and species. The importance of being able to identify mushroom by their scientific name with aide in the identification of those that are poisonous

4. Linneaus: Father of Biological Nomenclature
Developed the system of identification by genus and species in 1758
Classification based on morphology and sex
Introduced eroticism into botany
Based on Greek and Latin words that are often descriptive of the physical characteristics of the organism

5. Genus and Species Each species of an organism has a unique name
Closely related organisms are placed in the same genus
Some organisms given names to honor a scientist or other person
Some genus names are also common names (Pinus)
Species names are descriptive adjectives that may be used with more than one genus name

6. Genera: Ginko
Only surviving species in this genus, over 270 million years old

7. Genera: Pinus
A) Pinus resinosa B) Pinus strobus C) Pinus banksiana

8. Linnaeus borealis

9. Narcissus
Scientific name also used as a common name. Other examples are Hibiscus, Gladiolus, Vanilla

10. Species Names are Descriptive Adjectives
Epithets used for species names

11. Salvia divinorum
is a psychoactive herb which can induce dissociative effects. It is a herbaceous perennial in the Lamiaceae (mint) family. The specific name, Salvia divinorum, was given because of its traditional use in divination and healing[5]—it literally translates to "diviner's sage" or "seer's sage".[6][nb
Source

12. Subspecies
Subspecies – a group of organisms that inhabits a geographical area or type of habitat different from other members of the same species
Ex. Zea mays subspecies parviglumis (teosinte)
Corn in Mexico

13. Varieties and Cultivars
Varieties – members of the same species that have small but consistent differences from each other
Cultivar – a variety that does not occur in nature but occurs only in cultivation. Names selected to attract customers
Ex. Phlox paniculata
‘David’

14. Hybrid Names Crossbreeding between 2 species
Individuals that do not breed with parents become new species
Species names combine the names of the 2 species that crossbread
Ex. laeliocattleya = laelia + cattleya

15. Other Definitions
Herbaceous- plants with nonwoody stems which die back at the end of the growing season
Woody-plants that have woody stems
Evergreen – plants that stay green year-round
Deciduous-plants that lose their leaves in the winter
Perennial – plants that come back each growing season
Annual – plants that die after 1 growing season
Biennial - plants that die after 2 growing seasons

16. Resources for Identifying Plants
Herbariums – pressed and collected specimens
Serve as reference libraries in which thousands of plants from all over the world are stored

17. National Herbarium
The United States National Herbarium was founded in 1848, when the first collections were accessioned from the United States Exploring Expedition (50,000 specimens of 10,000 species). Current holdings total 4.5 million specimens, making this collection among the ten largest in the world representing about 8% of the plant collection resources of the United States.

18. Botanical Gardens Collections of living plants
Resource for botanists, landscape architects, and gardeners, artists and photographers
Serve to conserve rare species in danger of extinction

21. Dichotomous Key- a series of choices between
Dichotomous Key- a series of choices between two possibilities to determine ID

22. Modern Classification of Plants
Morphological features are deceiving and are not used to classify plants
Some unrelated plants may appear to be related because of similar leaf shape
Likewise, plants that are closely related may have very different leaf shapes

23. Ricinus (castor bean) and Begonia ricinifolia
Unrelated plants can have similar leaves – but not be related – this is a problem when classifying based on Morphology

24. Very different looking, but all begonia species
Very different looking, but all begonia species. Modern classification systems rely on a variety of characteristics including DNA sequences (molecular characteristics), structure and function of enzymes (biochemical characteristics), and structural characteristics to group organisms. Classification based on phylogeny

25. Linneaus used floral characteristics to classify plants
Flowers of different begonia species are very similar in form reflecting close relationship.
Linneas organized plants into 24 classes according to the number of male stamens in the flower

26. Hierarchy of Classification

27. Phylogenetic Systematics
Classification of organisms according to evolutionary relationships

28. Cladistics
A new method of classification using the number of characteristics that organism share in common and placing them in order on a phylogenetic tree (like a family Tree)
Clade – a group of organisms defined by at least one shared characteristic, derived from a common ancestor
Ex. All organisms producing seeds
Preferred method of classification today
Shape of a phylogenetic tree may change as new data becomes available
Focuses on evolutionary relationships rather than morphological characteristics

29. Cladogram of Land Plants
This tree illustrates the relationships in land plants. Illustrates which groups have specific characteristics, such as leaves and seeds Some shared characteristics such as seed production, present in some groups but not in all, indicate that all plants producing seeds had a common ancestor and diverged or branched away from non-seed producers at some time in the past.

30. Plant classifications may change as new discoveries are made
DNA serves an important role in providing links between species
Ex. Tomato (solanum licopersicon) and potato (solanum tuberosum) recently found to be so closely related that they belong in the same genus