Tree Identification
Ashley Peebles
Delaware Forest Service
Taxonomic Classification
The basic processes of classification are
grouping and ranking
KINGDOM
Grouping involves the sorting of objects
into groups that have some features in
common – Ranking is the organization of
the groups into a nested hierarchy of
small groups within progressively more
inclusive groups.
PHYLUM
CLASS
Each group that is recognized in the
classification hierarchy is called a taxon
ORDER
The lower the rank of a group, the
more similar are the organisms
grouped in it
FAMILY
GENUS
SPECIES
KINGDOM
PLANTAE
Bryophyta
NON-VASCULAR PLANTS
mosses
VASCULAR PLANTS
Pteriodophytes
SEEDLESS PLANTS
ferns
SEEDED PLANTS
Cycadophyta, Ginkgophyta,
Gnetophyta, Coniferophyta
GYMNOSPERMS
plants that do not flower
Magnoliopsida
DICOTS
Magnoliophyta
ANGIOSPERMS
plants that flower
Liliopsida
MONOCOTS
grasses
A species is group of closely related, structurally and functionally similar
organisms which can breed among themselves
KINGDOM
Suffix name emphasized
Metaphyta
Magnoliophyta
PHYLUM
CLASS
Magnoliopsida
Sapindales
ORDER
Aceraceae
FAMILY
GENUS
SPECIES
Acer
No standardized suffix
Acer rubrum
No standardized suffix
Tips for learning families
 Each plant family has its own pattern of variation
 No one species is truly representative of that pattern unless it is the only
member of its family
 Usually a family has several genera, each comprising one of more species.
They are united as members of one family because they share a set of
characteristics and are thought to share some common ancestry.
 A feature that is uniform in one family may be highly variable in another. These
“diagnostic features” are used to distinguish one from family from another.
 Usually no one feature by itself is diagnostic. Each family is characterized by a
combination of features.
!!! It is your task as a student develop a concept for each of the families you are
assigned to learn. This concept should be broad enough that you will be able to
recognize family members on sight, even if they are species or genera that you
have not seen before.
Disadvantages of common
names
 Common name given one language is not universally
helfpful
 Wide ranging plants may have several common names
 Sometimes two or more kinds of plants have the same
common name
 Some rare plants do not have common names
Bionomial nomenclature
Acer rubrum
 2 part scientific naming of species
 The first word is a noun, the name of the genus to which the
plant is assigned
 The second word is usually either an adjective or a
possessive noun
 Designated in Latin
 First adopted by Carl Linnaeus in 1753
Generic Names
 A generic name (name of a genus) is treated a Latin noun.
 It should be capitalized and either underlines or typed in italics
 Generic names comes from various sources but are all referred to
as the Latin name
Acer………………………ancient Latin for maple
Conium…………………..Latinized form of an ancient Greek name
Artemisia…………………Greek mythology- Artemis, the goddess of the hunt
Dimorphotheca………….Greek, meaning two forms of fruit
Trifolium…………………..Latin, meaning three leaves
Kalmia…………………….Named for Peter Kalm, a student of Linnaeus and
botanical explorer in eastern North America
Species Name
Quercus alba
 A species name is a two-word name that consists of a generic name and
a specific epithet. The specific epithet by itself is NOT a species name.
 The specific epithet is usually written in lower case and underlined or
italicized.
 May be descriptive of the plant, may refer to its geological range or it may
be descriptive of its habitat.
albiflora………….Latin compound meaning white-flowered
chrysantha………Greek compound meaning yellow-flowered
serrata……………Latin for saw-toothed
arvensis…………..Latin meaning for field
americana………..from America
pensylvancia………from Pennsylvania
The Dichotomous
KEY to Knowledge
 Keys are written to identify many groups in the natural
world i.e. trees, rocks, fish, fossils, wildflowers, ferns
 Keys consist of a series of choices that lead the user to
the correct name of an organism
 Compares different expressions of the same character
(flower red or flower white)
 Process of elimination
 Tree keys concentrate on leaves for identification
LEAF ANATOMY
petiole
midrib
leaf blade
margin
sinus
lobe
veins
TYPES OF LEAVES
Needles in bundles
Ex: pines, spruces, hemlocks, larches
Flattened, scale-like leaves
Ex: junipers and cedars
True leaves- petiole, blade and midrib
Ex: maples, oaks, cherries
LEAF COMPLEXITY
COMPOUND LEAVES
LEAF ARRANGEMENT
Alternate leaves
• One leaf and bud at every
node
Opposite leaves
• Two leaves and two bud at
each node
The only three tree species in Delaware with an opposite leaf arrangement:
MAPLE, ASH, DOGWOOD
LEAF MORPHOLOGY
Margins
LEAF MORPHOLOGY
Shapes
LEAF SURFACES
LEAF MORPHOLOGY
Venation
arcuate
pinnate
parallel
longitudinal
cross-ventulate
palmate
TWIG MORPHOLOGY
COMMON FRUITS
Reproductive structures are unique from species to species and
are great for identifying tree
• However, may only be available during certain times of the
year
OTHER DEFINING
CHARACTERISTICS
TWIGS AND BUDS