Unit 2

Plant Taxonomy: How Plants Are Named

Why are scientific names written in Latin?• The early scholars always wrote in

Latin or Greek, so naturally, when they described plants or animals, they gave them scientific Latin or Latinized Greek names.

• This caused problems because the names were often long and difficult.

To differentiate between scientific and common plant names and explain the binomial system of

naming plants • Most plants have more than one common name.

Common names can be confusing.• The Swedish botanist, Linnaeus, developed the

binomial (two name) system for naming plants.• All plants having the same generic name are said

to belong to the same genus. Plants belonging to the same genus have similar characteristics.

• The first name is the genus (plant group name) and the second the species (or kind)

• The genus name is usually a noun and the species an adjective

Plant Families

• Related genera (plural or genus) with similar flower structures are grouped together in major units known as families.

Binomial System• Some common genus names are:

– Acer (maple), Chrysanthemum (mum), Dianthus (pink), Hibiscus (mallow), Sedum (stonecrop), Papaver (poppy), Pinus (pine) and Pelargonium (geranium).

– In some cases, the generic (genus) name has become the common name (Euronymus, Rhododendron and Forsythia)

• The species name often gives us information about the plant. It sometimes tells us the color (lutea means yellow, alba means white, ruba means red, nigra

means black) or if the plant is creeping or erect (repens

is creeping) Sometimes the species name gives geographic information about where a plant occurs naturally (Anemone virginiana from Virginia, Taxus canadensis from Canada)

• When writing a scientific name, the genus name always begins with a capital letter and the species name with a small letter.

The Taxonomist

• Scientist who identify and classify plants are known as taxonomists.

• An international set of rules drawn up to ensure that every different species has a different binomial name and that the scientific name assigned to that plant is the oldest binomial name ever used is known as the “ International Code of Botanical Nomenclature”

Student Activities• Complete self evaluation at the

end of the unit.• Get a plant catalog or book and list

20 common plant names and their scientific names in proper form like the following example:

Scientific Name Common Name

Acer rubrum RED MAPLE