I. Taxonomy
A. Identification
B. Nomenclature
C. Classification
II. Nomenclature = System of naming things
A. International Code of Botanical Nomenclature
1. Botanical Code independent from Zoological Code
2. Application of name determined by types
3. Each taxonomic unit can have only one valid name
4. Oldest valid name always has precedence
5. Names treated as Latin regardless of derivation
6. Rules
are retroactive from 1753
B. Binomial System of Nomenclature
1. Generic Name 2. Specific Epithet 3. Authority
Populus deltoides Bart. ex Marsh.
2. Generic Name
a. Always a singular, nominative case noun
b. Always capitalized
c. May be:
1. Descriptive of some characteristic
eg. Liriodendron = lily or tulip tree
2. Aboriginal name
eg. Following are Latin
Quercus = oak
Fagus = beech
Betula = birch
3. Honoring some person
Linnaea = Carolus Linnaeus (Carl Linne')
3. Specific epithet
a. May be:
1. Adjective, agreeing with generic name in
gender, usually indicating
a. distinquishing characteristic
Rosa alba = white rose
b. where first discovered
Ulmus americana = american elm
2. Noun in opposition, always in nominative
case, but doesn't have to be same gender
as generic name
Pyrus malus = apple
3. Noun in genitive singular or plural,
honoring a person
Carex davisii = honoring Mr. Davis
4. From common name, genitive plural, usually
indicating something about habitat
Convolvulus sepium = of the hedges
III. Plant Classification = Arrangement of plant groups in some
systematic order
A. Artificial Classification: order facilitates
identification
of unknown types of plants
B. General Purpose Classification:
order reflects general
genetic relationships
and those morphological characters
that are easy
to identify
C. Phylogenetic Classification:
order represents the
degreee to which
plant groups have evolved from one
another or with
one another (parallel evolution)
1. Often
assumed that similarity correlates with recency
of common ancestory
2. Assumed
that best genetic relationshipss among groups
of plants are reflected
IV. Taxonomic heirarchy = Method of classification of plants in
a
heirarchy or in an order of rank which corrresponds
to greater
and greater degrees of relatedness among members
of each rank.
Kingdom eg. Plantae = plants
(cellulose cell wall,chlorophyll a and b)
Division
eg. Magnoliophyta (Anthophyta) = angiosperms
(ovules enclosed in ovary)
Class eg. Magnoliopsida (Dicotyledonae) = dicots
(two cotyledons)
Order eg. Salicales = willow (simple,
alternate leaves with stipules, catkins,
pubescent seeds)
Family eg. Salicaceae (leaves deciduous,
dioecious, fruit 1 celled 2-4 valved
capsule)
Genus eg. Populus (leaves as long as
broad, buds covered by
imbricated scales)
Species eg. Populus deltoides
(deltoid leaves with
compressed petioles and
glandular apices)
V. What is a species?
A. "Recognizable and self-perpetuating
population that is
more or less isolated genetically as well as by its
geographical distribution and environment"
B. Barriers which isolate populations genetically
1. Internal
a. expressed through incompatibility of gametes or
sterile hybrid offspring
SPECIES A X SPECIES B -->> No offspring
or,
-->> Sterile offspring
b. genetic or physiologic in nature
2. External
a. Environmental
SPECIES A grows in high mountains
SPECIES B grows in low river valleys
b. Geographic
SPECIES A grows on west coast
SPECIES B grows on east coast
c. Temporal
SPECIES A flowers in early spring
SPECIES B flowers in late fall