POLLEN AND SPORE
EXAMINATION
INTRODUCTION

Pollen and spore information can be used to
determine the following:
Was the body moved?
 Where did the crime take place?
 What season did the crime take place?
 Did the crime take place in the day or night?

Forensic Palynology – study of pollen and spore
evidence to help solve a crime.
 Pollen – contains 2 sperm from seed plants
 Seed – a fertilized egg. Will develop into an adult
plant.
 Spore – small structure that grows and develops
into an adult in algae, ferns, moss, and fungi (like a
seed).

POLLEN PRODUCERS
 Pollen
“fingerprint” – number and
type of pollen grains found in an
area at a particular time of year.
 Plant kingdom is divided into two
groups based on how they reproduce:
seeds or spores.
 Seeds: Gymnosperms (evergreens)
and Angiosperms (flowering
plants)
 Spores: Ferns, moss
GYMNOSPERMS
Means “naked seed” – the seed is not protected
like they are in flowering plants
 Most numerous group of gymnosperms are the
conifers (evergreens)
 Produce their seeds within a cone. Here’s how:

Pollination occurs when pollen lands on a female
cone, grows and releases the sperm near the egg.
 Once the egg is fertilized, a seed develops (containing
an embryo)

ANGIOSPERMS
Flowering plants
 Produce seeds within an enclosed fruit
 Parts of a flower:

TYPES OF POLLINATION
 Important
in forensics in determining the
presence or absence of pollen in a place or
on an object of a crime scene
 Self pollination vs. Cross pollination
 Self – pollen transfer from anther to
stigma within the same flower.
 Cross – pollen transfer involving two
distinct plants
 Self pollinating plants has lower value
because they produce less pollen
METHODS OF CROSS POLLINATION
 Wind
pollination – produce a lot of pollen (good and bad)
 Good – well represented in the pollen profile of
a crime scene
 Bad – less effective in determining direct links
 Flowers are usually nonfragrant, lack color,
small
 Animal pollination– insects, birds, bats, monkeys
 Flowers are fragrant and “showy”
 Pollen grains are durable and can adhere to
things
 Strong evidence of contact
 Produce less pollen
POLLEN GRAINS UP CLOSE
METHODS OF POLLINATION CONTINUED
 Water
pollination
 Rarely preserved because it is composed
of only a single layer cell wall made of
cellulose
 Pollen will decompose if removed from
water
 Limited use, excepts for drowned
victims…contents of the lung can be
emptied and analyzed.
SPORE PRODUCERS

Algae


Adapted for dispersal in water or air
Ferns and Mosses
Release spores into the air
 Because of this, forensics is most interested in these, why?


Fungi
Produce a large amount
 Mold, yeast, mushrooms
 Can be found practically everywhere, not so interesting,
why?

Mushroom
spores
SPORE DISPERSAL





Wind
Water
Spore ejection
Animal disperal (they eat the
spore and deposit it somewhere
else in their feces)
Spore analysis has one advantage over
pollen…it is possible to grow the organism and
identify the species exactly.
POLLEN AND SPORE IDENTIFICATION IN
SOLVING CRIMES

Exine -- The hard outer layer of a pollen or spore
grain

Has a unique and complex structure under the
microscope.
Larger pollen grains can’t travel far (can only
drift with the wind ½ mile) (corn)
 Wind-dispersed pollen grains are simple, have
thin walls, easily preserved
 Animal-dispersed pollen grains are large, sticky,
highly ornamented, thick-walled and easily
preserved

POLLEN AND SPORE IDENTIFICATION IN
SOLVING CRIMES CONTINUED

Identification of pollen and spore grains is species
specific
Help determine season
 Help determine location
 If not native to the crime scene, body was moved.

Pollen and spores are difficult to eliminate by the
suspect because they are microscopic
 They are resistant to dehydration and
decomposition (can be found in sediment from
millions of years ago)
