Transcript Plant Taxonomy

Plant Taxonomy- is the grouping of plants based
on their presumed relationship.
Nomenclature is the application of names to
plants.
Common Names are easy to pronounce and
remember, but they can be confusing because
of different areas use different names.
Scientific names are formal names accepted by
scientists around the world.
Scientific names of taxonomic groups are
treated as Latin regardless of their derivation.
Scientific names have a Genus name, the
specific epithe, and the authority of individual(s)
responsible for the name.
The genus and species name are either italicized
or underlined.
The scientific name for the white oak is Quercus
alba L.
Scientific names published at the earliest date
take precedence over names of the same rank
published later.
In order to have a definite starting point,
botanists have agreed that for flowering plants
the starting point shall be Species Panktarum,
published by Carl Linnaeus in 1753.
The International Code of Botanical
Nomenclature lists exceptions and additions to
this rule.
The code is supposed to keep botanists all over
the world using the same system names.
There is a disagreement over some plant
groupings today, and we have several proposed
classification systems.
Some of these systems have 20 or more principal
groups of plants.
The major classification groups for Botany and
Zoology are different.
There is movement to adopt only one classification
system, The Bio Code, for all types of living things.
Most literature usually refers only to one family name,
and the genus and species of individual plants.
Botanists have adopted the Type Method to stabilize
the determining characteristics of a species.
The author of a species must designate a certain
specimen as the Type Specimen of that species.
The Type Specimen is not necessarily the most
representative of the group, it just best shows the
element on which the name for the group was
originally based.
The Type Specimen fixes the strict concept of that
species and the application of its name.
Type Specimen is carefully preserved in a herbarium
that is accessible to research scientists.
To allow for destruction of the Type Specimen, the
system Isotope, Lectotype, Neotype, and others were
devised for designating acceptable substitutes.
Holotype (Type Specimen) is the original specimen
designated by the author. Types are the most
valuable of all the specimens.
Museums and Universities are very proud of the
number of Type Specimens they have in their
hebarium.
Isotype is any specimen, other than the holotype,
that duplicates the holotype. The isotope must come
from the same collection, with the same locality,
date, and number as the holotype.
Lectotype is a specimen selected by a competent
person from the original material studied by the
author.
Neotype is a specimen selected to serve as a
substitute for the hologype when all material on
which the name was based is missing.
Gymnosperms form “naked seeds”, not
enclosed in fruit.
Division Cycadophyta- only about 100 species of
cycads are alive today, most of which are found
in the tropics.
Division Ginkgophyta- is the only living ginkgo
example is Ginkgo biloba. The Ginkgo is a hardy
delicious tree that is planted as an ornamental.
Division Coniferophyta- conifers are woody
plants with needle or scale-like leaves that form
cones. They include pines, cedar, junipers,
redwoods, firs, and spruce.
Angiosperms for their seeds enclosed in a fruit.
Division Anthophyta- flowering plants. There are
almost 300,000 species of angiosperms, making
them dominate group of plants in the world
today.
There are two classes of Angiosperms, based on
their number of cotyledons (seed leaves)
Monocotyledoneae (the Monocots)- all members
of the group have one ctyledon.
Monocots have about 90,000 species, 10% of the
species are woody, most are grasses and grains,
such as wheat, oats, corn, and rice.
Dicotyledoneae (The Dicots)- all members of this
group have two cotyledons
Dicots have almost 200,000 species.
Dicots are 50% woody, and are a very diverse
group.
Monocots and Dicots are the two most important
groups to study.
In this class, you will be able to differentiate
between Monocots and Dicots.
Plants are sometimes grouped using the
common names below.
While these are not taxonomy groups,
understanding their use is very helpful!
Tree- woody plants with
one main stem or trunk
Shrub- woody plants with several
stems growing from the ground
Forb- Herbaceous(soft-non woody)
plants with flowering leaves
Grass-Herbaceous flowering plants
with narrow leaves and jointed stems.
Succulent- Plants with thick, fleshy tissue in
leaves or stems for storing water
The following terms are applied to herbaceous plants
with green, non-woody stems.
Annual plants- live for one growing season. They will
sprout, grow leaves and flowers, produce seeds, and
die.
Biennial plants- complete their lifecycle over two
growing seasons. In the first season, they usually
only produce leaves. In the second season, they
form flowers, produce seeds, and die.
Perennial plants- continue to grow and flower for
more than two years, and many live for decades.
Most perennials die back to the ground in winter, the
sprout from their underground growth in the spring.
Example of Annuals
Example of Biennials
Example of Perennials