Horticultural Taxonomy or Systematics
This is a Horticultural Taxonomy or Horticultural Systematics class.
The terms Taxonomy and Systematics are often used interchangeably today. This is a broad
field concerned with the study of the diversity of plants and their identification, naming,
classification, and evolution.
Plant taxonomy or systematic botany attempts to classify plants into a system which reflects
both evolutionary relationships and presently existing similarities and differences. Evidence
from all sources is used in arriving at a taxonomic system, but external morphology is usually
emphasized because it provides so many characters that can be easily seen and measured.
A taxonomist is one who uses many approaches to fit together appropriately, into an orderly
storage and retrieval system with a name reference base, the information about plants.
This information is gathered by morphologists, anatomists, cytologists, palynologists,
embryologists, geneticists, physiologists, biochemists, ecologists, geographers, paleobotanists,
A taxonomist is a collector, organizer, and synthesizer of information from all fields of evidence
for the characterization and classification of plants.
Plant Taxonomy is divided into five major areas:
1. Classification = The arrangement of plants into groups having common characteristics. This is
for the purpose of easy reference and to communicate intelligibly with others. A hierarchy of
levels is used to reflect evolutionary relationships. Because the taxonomy of cultivated plants is
difficult (plant breeding has modified the natural plant species), the classification of many
cultivated plants is in need of revision. Researchers in taxonomy prefer to study natural plant
populations and their evolution.
2. Nomenclature = Orderly application of names to plants in accordance with the:
a. International Code of Botanical Nomenclature.
b. International Code of Nomenclature of Cultivated Plants.
The application of a set of rules for naming plants.
These are revised every 5 to 10 years at International Botanical Congresses. They are published
by the International Bureau for Plant Taxonomy and Nomenclature of the International
Association for Plant Taxonomy.
3. Identification = Determining if a plant is identical with or similar to an already known plant.
The recognition of certain characters of flower, fruit, stem, leaf, etc. and the application of a
name to a plant with those particular characteristics.
Use plant keys.
Compare to known living plant.
Compare to dried Herbarium specimen.
4. Phytography = Using descriptive terminology to list the features and characteristics of a plant.
The description of plants and their various parts. The chief objectives of phytography are
accuracy and completeness of description without undue wordiness.
In this class we will discuss terms as we come to them.
Most of the class texts include a glossary of terms.
5. Documentation = The making of Herbarium specimens to document research or record plants
of a particular area. A Herbarium is basically a museum of pressed and dried plants. These
specimens are used for identification and for research studies. Since they were collected over
many years, they are a record of plant characteristics and diversty.
Researchers working on a specific group of plants can borrow from all the major herbaria in the
United States and Canada. After the study is completed, the specimens have annotation labels
attached, which helps to verify and update the specimens.
Herbarium specimens are especially useful for sources of flowering and fruiting dates,
geographic ranges, etc. Dr. Voss used herbarium specimens frequently in preparing the
Some botanical and horticultural research is not verifiable because no herbarium specimens were
filed in a recognized herbarium. Many early chromosome counts in plants are invalid because
there are no herbarium specimens available to verify that the correct plants were used.
See Instructions for preparing herbarium specimens.
The Beal-Darlington Herbarium is in the Botany Department and includes about 600,000
specimens. All species of Michigan plants are represented along with selected species from
around the world. The plants of Mexico, and the plants in the Compositae or Aster Family are
also very well represented.