Forensic Botany

Forensic botany is the application of the plant sciences to legal matters. Most often this means using clues from plants in order to aid in the solution of serious crimes such as murder, kidnapping, and the cause of death of a victim. Many aspects of plant science are employed, including plant anatomy, the study of plants cells; plant taxonomy, which deals with the identification of plants; plant systematics, focusing on plant relationships to other plants; plant ecology, which deals with plants and their environments; and palynology, which is the scientific study of plant pollen and spores.

Plant cells possess cell walls made of cellulose, a complex carbohydrate compound that is virtually indestructible in comparison with most other natural compounds subject to decay. Plant cell walls can remain intact for thousands of years even though the cytoplasm long since has disappeared. The walls around pollen grains and spores also are made of different materials that are also resistant to decay. This allows plant parts to remain identifiable for long periods of time.

The plant foods we consume have distinctive cells within them. The tissues of food plants are made up of cells of distinctive shapes and sizes that are arranged in distinctive patterns. These characteristics are preserved all the way through the human digestive tract and beyond. This also is true for wood. This means it is possible to tell what a person's last meal was long after death. Also, if a person was stuck with a piece of wood, that piece often can be identified to species and/or matched to the larger wood piece from which it was obtained. Sometimes seeds, leaves, and plant fragments are associated with a crime. If the plant can be identified from these clues by a plant taxonomist, they may link the crime to a specific place (for example, one associated with a suspect). Also, taxonomists can be called upon to identify drug plants that are illegal in this country, such as coca.

Plant ecology has been found useful in the location of the graves of missing persons. It does not matter whether the grave is deep or shallow or whether the person was clothed, encased in plastic, or naked at the time of burial. The clues for the burial site come from the necessity of disturbing vegetation cover to dig a grave. A knowledge of plant succession patterns in the area is almost impossible to disguise from the eyes of a well-trained plant ecologist. They remain evident for at least a few years, and sometimes for a decade or more.

Palynological evidence can be used to suggest where a person was killed and to link a suspect to a crime scene. It also can be used to identify controlled (illegal) plant substances even if no other plant material is present.

Forensic botany is a new and growing field. Many criminal investigators, medical examiners, and attorneys are unaware of its usefulness because they have had little exposure to botany in their educational experiences. Most forensic botanists act as private consultants in crime matters. To be accepted to testify in a court case, forensic botanists must demonstrate that they are qualified to be expert witnesses. Their suitability for such testimony is judged by their experiences and educational credentials.

see also Palynology; Plant Community Processes.

Jane H. Bock

David O. Norris

Bibliography

Bock, Jane H., and David O. Norris. "Forensic Botany: An Underutilized Resource." Journal of Forensic Sciences 42, no. 3 (1997): 364-67.

France, D. L., T. J. Griffin, J. G. Swanberg, J. W. Lindemann, G. C. Davenport, and V. Trammell. "A Multidisciplinary Approach to the Detection of Clandestine Graves." Journal of Forensic Sciences 37 (1992): 1445-58.

Lane, M. A., L. C. Anderson, T. M. Barkley, J. H. Bock, E. M. Gifford, D. W. Hall, and D. O. Norris. "Plants, Perpetrators, Pests, Poisons, and Pot." BioScience 40 (1990): 34-39.