Forenisc
Botany
Spring 2013
Forensic Palynology
 The
use of pollen and spore evidence to
help solve criminal cases
Some Vocabulary
 Angiosperm-
a flowering plant that
produces seeds within a fruit
 Exine- outer layer of the wall of a pollen
grain or spore
 Gymnosperm- a plant with naked seeds
that not enclosed in a protective
chamber (fruit), such as an evergreen
 Pistil- the female reproductive part of a
flower where eggs are produced
Some Vocabulary
 Pollen
“fingerprint” (aka pollen profile)the number and type of pollen grains
found in a geographic area at a
particular time of year
 Pollen grain- a reproductive structure that
contains the male gametes of a seed
plant
 Pollination- the transfer of pollen from the
male part to the female part of a seed
plant
Some Vocabulary
 Spore-
an asexual reproductive structure
that can develop into an adult found in
certain protists (algae), plants, and fungi
 Stamen- the male reproductive part of
the flower consisting of the anther and
filament where pollen is produced
Pollen Producers
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The plant kingdom is broken down into 2
groups: non-seed plants and seed plants
The earliest plants were non-seed plants, they
reproduced using spores
Seed plants make pollen to disperse male
gametes (“sperm”)
There are 2 groups of seed plants:
angiosperms and gymnosperms
Both types are land plants are likely to leave
trace evidence
Pollen Producers
Non-seed Plants
Seed Plants
Ferns
Mosses
Liverworts
Horsetails
Club mosses
Gymnosperms
Cycads
Ginkgoes
Conifers
Angiosperms
Flowering plants
Gymnosperms
 Gymnosperms
are the oldest seed plants
 Seeds are exposed to the outside and not
enclosed (like in angiosperms)
 Called “evergreens” because they retain
their leaves and needles throughout the
year
Gymnosperms
Gymnosperms
Many conifers produce
seeds with a hard cone.
 Female cones- Larger
& open. Contain eggs
Inside ovules.
 Male cones- Smaller &
occur in clusters. Release
large amounts of pollen
to be spread by the wind.

Angiosperms
 Flowering
plants that produce seeds in
enclosed fruits
 Include corn, maples, oaks, and grasses.
 Very successful and widespread group
with over 300,000 species known.
 Because angiosperm plants are found in
so many places, many different crime
scene areas are likely to contain samples
of angiosperm pollen.
Angiosperms
 Pistil
is the female
part.
 Stamen is the male
part.
 Pollen lands on the
stigma and travels
down the style to
the ovary.
 There may 1 or
hundreds of eggcontaining ovules
within the ovary.
Angiosperm Fruit
Pollination
 Pollen
dispersal patterns are an important
consideration at a crime scene. The
pollination strategy of a plant is important
in determining the presence or absence
of pollen in a place or on an object at the
scene.
Pollination
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Self-pollination- transfer of pollen from the
anther to stigma of the same flower (pea
plants)
Cross-pollination- transfer of pollen from the
anther of one plant to the stigma of another
plant
Some plants perform both pollinations
Self-pollinating plants are of lower value in
forensics because they produce less pollen
and exist in small numbers
Methods of Pollination
 Wind
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Generally have small, non-fragrant flowers
 Animal
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(insects, birds, bats, monkeys)
Flowers of these plants must be very
fragrant and colorful!
 Water
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Sea grasses, composed only of a singlelayered cellulose wall
Wind Pollination
 Wind-pollinated
plants produce large
amounts of pollen
 This allows them to be well represented at
a crime scene
 This could make it less effective for
determining links between individuals
and places
Animal Pollination
 Make
adhesive and durable pollen
 This allows them to be more likely
collected as evidence
 Can provide strong evidence of contact
because the pollen can only be directly
transferred
 Animal-pollination plants produce less
pollen so they tend to be underrepresented at a crime scene
Water Pollination
 Aquatic
plant pollen is release under the
water which means it is rarely preserved
and generally decomposes if removed
from the water.
 Very limited use for forensics
 An exception would be drowning victims.
Contents of lungs could be examines for
pollen and other debris.
Spore Producers
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Include certain protists
(algae), plants, fungi
and some bacteria
Algae- spores are
adapted for dispersion
in water or air
Land Plants- produce
spores from a structure
called sporangium, gills
or sori.

Ferns and mosses
release spores into
the air
Spore Producers
 Fungi-
include
baker’s yeast, mold
and mushrooms
 Produce spores
sexually and
asexually
 Released by wind
and water
 Are found
everywhere
Spore Producers
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Bacteria- Some bacteria form thick-walled,
resistant spores, called endospores when
environmental conditions are harsh
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Endospores are different from other spores
because they are not used in reproduction. The
bacteria only produce 1 at a time.
These are important to forensics because
several types of bacteria have been used as
bioterrorism agents (anthrax and botulism)
Pollen & Spore Identification in
Solving Crimes
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The exine (hard, outer layer) of pollen and
spores is unique to plants.
Looking at shape, size, wall thickness and
surface texture (such as spines) can help
determine type/species of plant.
Example: Large pollen from corn cannot
travel far (about ½ mile in the wind). If a body
had corn pollen on them, then they were
probably close to a corn field or flower.
Pollen & Spore Identification in
Solving Crimes
 Wind-dispersed
pollen and animaldispersed pollen are both easily preserved
for identification.
 Spores are smaller than pollen and
produced in a much larger number.
Spore evidence can be harder to find if it
is not concentrated.
 Spores are more difficult to identify than
pollen as far as species.
Pollen & Spore Identification in
Solving Crimes
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Both pollen and spores are both good for
season and geographical location
identification
An indication a body has been moved is
evidence of spores or pollen not native to the
crime scene
Both pollen and spores are hard for criminals
to eliminate because they are microscopic
Most pollen and spores are resilient to
dehydration and degradation.
Criminals can easily pick these up on their
shoes and clothes.
Where can you find pollen
and spores?
 Living
and decaying plant matter
 Soil, dirt, mud, dust
 Hair, fur, feathers
 Clothing, shoes, blankets, rugs, carpet,
rope
 Victim’s skin, hair, nails, nasal passage,
lings, stomach, intestines and fecal matter
 Paper, money, packaging material
Where can you find pollen
and spores?
 Vehicles
 Furniture
 Air
filters in cars, homes, planes
 Cracks and crevices of floors, walls, roofs
and fences
 Drug resins
 Honey and other food