Plant names and classification

Why classify?

•When you have a lot of things to keep track of, it is helpful to have an organizing scheme.

•Where do you look for cookies at the grocery store? 

•How do you tell your friend where you live? 

•How do you find your favorite CD at the music store?


•With as many living things as there are in the world, we need a good way to keep track.

The Kingdom Concept

•Two Kingdoms (an early system)

1. Plantae

• nonmotile, photosynthetic autotrophs

2. Animalia

• motile, ingestive heterotrophs


The Kingdom Concept

•Two Kingdoms

•Problem of the euglenoids

Euglenoids (single-celled organisms) are motile and ingestive, but also  have chloroplasts and can do photosynthesis

The Kingdom Concept

•Two Kingdoms

•Problem of the slime molds

While feeding look and behave like amoebas, but during reproduction, they become stationary and develop fungus-like reproductive bodies


Five Kingdoms

•Proposed by R. H. Whittaker in 1969

•Divided complex organisms on forms of nutrition

–Photosynthesis: Plantae 

–Ingestion of solid food: Animalia

–Absorption of nutrients in solution: Fungi

•Divided simple organisms on basis of cell type

–Prokaryotes: Monera (bacteria)

–Eukaryotes: Protista (algae, sponges, slime molds)

•Lichens do not fit (combination of algae and fungi)

The Taxonomic Hierarchy

Within kingdoms are a series of nested, smaller groups


            phylum (or division)   








Higher categories are more inclusive


The Taxonomic Hierarchy

Classification of an onion


Kingdom          Plantae

            phylum             Magnoliophyta

                        class                             Liliopsida

                                    order                             Liliales                       

                                                family               Liliaceae

                                                            genus                           Allium 

                                                                        species               Allium cepa


Species name is composed of two words, the genus name and the specific epithet.

The Taxonomic Hierarchy

Classification of

            Pinus contorta var. latifolia (lodgepole pine)

Kingdom          Plantae

            phylum             Pinophyta

                        class                             Coniferopsida

                                    order                Coniferales                 

                                                family               Pinaceae

                                                            genus                           Pinus  

                                                                        species      Pinus contorta

                                                                                    (subspecies)                                                    (variety) Pinus contorta var. latifolia


Species names

•Why use scientific and not common names?


•Some species have more than one common name:

–Oregon myrtle in OR

–California bay in CA

–Umbellularia californica

–Plantago major has over 100 common names in several languages

•Some common names are used for more than one species

–Cedar is used for species in at least 4 different general and two families

–Cedrus, Thuja, Chamaecyparis, Juniperus

Species names

•Carl Linnaeus (1707-1778) proposed a                new system for naming plants

•Old system used Latin phrase names

•For example, spearmint was known as:

•“Mentha floribus spicatis, foliis oblingis serratis”

•(Means mint, flowers in spike, leaves oblong and serrate)

•Linnaeus proposed a system called binomial nomenclature

•Spearmint becomes

–Mentha spicata

Classification of Kingdom Plantae

•Plant kingdom divided into phyla according to

–modes of reproduction and

–complexity of tissues

•The 12 phyla can be lumped into four major groups



Classification of Kingdom Plantae

Non-vascular plants

•Simplest plants, reproduce by spores instead of seeds, lack the vascular tissue which allows plants to get large

Classification of Kingdom Plantae

Vascular, non-seed plants (ferns and their allies)

Classification of Kingdom Plantae

Gymnosperms - “naked seeds”, have vascular tissue, bear seeds not enclosed in fruits

            conifers, ginkgos, cycads


Classification of Kingdom Plantae

Angiosperms - “vessel seeds” bear seeds enclosed within fruits, flowering plants.

•One phylum, Magnoliophyta

–divided into two classes

–Magnoliopsida - Dicots

–Liliopsida – Monocots

•These are the plants we are most familiar with



Monocots and Dicots


•Seed with one cotyledon

•Flower parts in threes or multiples of three

•Leaf with parallel veins

•Vascular cambium absent

•Vascular bundles of stem in a scattered arrangement

•Vascular tissue of root arranged in ring

•Pollen grains with one aperture


•Seed with two cotyledons (seed leaves)

•Flower parts in fours or fives or multiples of these

•Leaf with netted veins

•Vascular cambium present (in older plants)

•Vascular bundles of stem arranged in ring

•Vascular tissue of root arranged in center

•Pollen grains with three apertures


Monocots and Dicots


Two major groups of trees


•Flowering plants

•Produce seeds in fruits



•Mostly deciduous (here)

•Maples, oaks, cottonwoods, alders


•Mostly conifers

•Seeds in cones



•Mostly evergreen

•Firs, pines, hemlocks, cedars, yews

Life Cycle


–plants which complete life cycle in single season


–plants which complete life cycle over two year period


–plants which live for more than 2 years and may flower at various times

•Woody plants are perennials with above-ground parts living more than one year

•All non-woody plants are herbs, or herbaceous plants.