FORENSIC BOTANY

•	The Exchange Principle, now called Contact Traces, first articulated by Edmond Locard in 1910

•	Trace botanical evidence can link an object or suspect to the scene of a crime

•	Rule out a suspect or support an alibi 

•	Provide vital information about a crime scene or the whereabouts of a suspect or victim 
Charles Lindbergh, Jr.

Rail # 16
•	Rail # 16 had four holes produced from 8 penny nails that had nothing to do with the construction of the ladder…suggesting previous usage
•	No signs of usage
–	Nail holes were not rusty
–	Wood was bright and did not show signs of bleaching
–	Used for rough construction, not finishing

FORENSIC BOTANY
Subdisciplines of plant science
•	Palynology
•	Anatomy
•	Dendrochronology
•	Ecology
•	Limnology
PALYNOLOGY
Fossil and modern pollen grains, spores, etc.
•	main forensic application: provide associative evidence
–	establish or disprove links among people, places, and objects  
PALYNOLOGY
PALYNOLOGY
SOURCES OF POLLEN EVIDENCE (Bryant et al., 1990)  
•	Dirt and mud
•	Hair and fur 
•	Cloth and ropes 
•	Packing materials 
•	Human remains; from the soft tissues of the stomach and intestines of corpses or the nasal passages of skeletons 
•	Imported/exported goods, often to verify country of origin
•	Antique goods, to validate age and authenticity
•	Air filters, to determine where private vehicles may have traveled 
•	Money suspected to have been used in drug transactions may be sampled for pollen of narcotic species 

ANATOMY
•	long used by archeologists and paleontologists to characterize archeological sites
•	increasingly more common in forensic applications after 1930’s
•	Anatomy is often taxon-specific

DENDROCHROLOGY
•	Dendrochronology is the study of tree rings 
•	annual growth: gradually smaller in radius as the growth season proceeds 
•	abrupt change in size from small, late season cells to the large, early season cells
DENDROCHROLOGY
Forensic applications
•	dating of wooden objects 
•	matching objects with crime scenes using the wood's morphological features
–	Art Fraud - provenance of wooden art objects and musical instruments
–	Lindbergh case 
ECOLOGY
•	Forensic analyses require the identification of botanical evidence
•	Useful to investigators in two ways
•	determine if plant fragments recovered from a victim came from recovery site (Lane et al., 1990)
•	Locating clandestine graves 

ECOLOGY
•	Knowledge of plant succession can help investigators locate hidden graves. 
•	When soil is disturbed for a burial, it does not remain bare for long; (pioneer species) 
•	The change in species composition of a site can be predicted to some extent for some geographical locations and habitat types. 
•	Potential burial site: If a certain localized site shows a different successional stage than the surrounding area, this is an indication of a disturbances (up to 20 years)
ECOLOGY
IDENTIFYING CONTROLLED SUBSTANCES (derived from plants)
•	marijuana (Cannabis sativa L.), 
•	opium poppy (Papaver somniferum L.)
•	peyote (Lophophora williamsii) 
LIMNOLOGY
The study of freshwater ecology
•	The algal community, particularly the diatoms, is especially useful in linking suspects and victims to crime scenes in or around fresh water

LIMNOLOGY
•	Species are easily identified from the characteristic shape of the cells and unique refractive pattern caused by the silica 

•	Seasonal variation in diatom abundance and diversity is used to generate floral profiles 

•	Diatom tests are used routinely in:
–	the diagnosis of drowning, and 
–	in estimating the post-mortem interval
LIMNOLOGY
DIAGNOSING DROWNING
•	Diagnosis of drowning can be very difficult
•	When a person drowns in fresh water, diatoms are taken not only into the lungs but are also dispersed among other internal organs 
•	Even when there are only skeletal remains, diatoms can be detected in the bone marrow of drowned victims 
•	20 diatoms per 100 microlitres of pellet from a 10 gram lung sample, or five complete diatoms = a positive diagnosis
LIMNOLOGY
Estimating PMI
•	Diversity of colonizing taxa increase over the course of 31 days (algal colonization patterns) 

•	Fewer than 20 colonizing taxa implies recent submersion, while more than 50 taxa indicates submersion for several weeks. 

•	Key indicator taxa can narrow the time frame down even further