INTRODUCTION

We are familiar with plants being used for pleasant and aesthetic purposes such as a source for food, fiber, medicine, etc. But the association of plants with cases such as poisoning (which can be suicidal, accidental, or homicidal), or its use as a trace/transfer evidence in criminal as well as civil cases is increasing with each passing day. When plants become linked to criminal activities, that is when Forensic Botany comes into play.

Forensic botany is the utilization of the plant sciences in matters related to law, i.e., using plants or plant products as evidence to help solve crimes such as murder, kidnapping, etc., and also to help determine the victim’s cause of death. Forensic Botany is an integration of Botany and Forensics. The botanical aspect majorly consists of anatomy, growth, development, taxonomy, classification of plants that help in the identification of the particular species of the plant, whereas the forensic aspect deals with the recognition of appropriate evidence at the crime scene, collection, and packaging of evidence, maintaining the chain of custody, conducting scientific tests on the samples collected and admissibility of the evidence in the court of law.

One of the most important reasons why plants are considered very good and useful evidence is that the cell wall of plant cells, as well as pollens and spores, are made of strong compounds such as cellulose, sporopollenin, and pectin which are resistant to destruction and thus can be identified even after a long period.

Forensic botany was first used to solve a crime in 1935. It was the Lindbergh Case in which a young boy named Charles Lindbergh had been kidnapped. The prime suspect of this case was Bruno Hauptmann. Arthur Koehler, an expert of wood anatomy was amongst the many people who testified. Even though the defense thought that the concept of the wood expert was too bizarre and ridiculous, but the Judge thought otherwise. Arthur Koehler presented evidence related to the ladder that was used in the kidnapping, stating that it was a homemade ladder and also stated the different types of wood that had been used to build the ladder. And one of the woods that was used to build the ladder was proved to be the same wood that was found at Hauptmann’s house, thus linking him directly to the crime.

Since then forensic botany has gained a lot of importance and has been used more and more to solve many such crimes.

BRANCHES OF FORENSIC BOTANY

The various branches of forensic botany are applied during the determination of the identity of criminals. These branches help in doing so by focussing on either the composition of plants or the association of plants with the environment in which they are present.

Forensic Plant Morphology: Plant morphology is the study of the external features of the plants. The external features may aid in the identification of the species of the plant. Thus, Forensic Plant Morphology refers to the application of this knowledge in the investigation of crimes. Besides, these features or the external structures help in making a match between two leaf fragments, thus showing the continuity of leaf patterns on the surface of the leaf.

Forensic Plant Anatomy: Plant Anatomy refers to the study of the internal structure of plants. Plant Anatomy helps in the identification as well as classification of the plants based on specific patterns of arrangement of the cells, which are observed on dissecting the stem, root, or leaf. Forensic Plant Anatomy is the utilization of this knowledge in solving crimes.

Forensic Palynology: Palynology broadly deals with the study of pollen grains, spores, and microscopic plant bodies that possess a characteristic feature resistance to acidity. Palynology further helps in proving or disproving a possible link between particular people, objects, and places (crime scenes) that acts as vital information for the investigation of both civil as well as criminal cases. One of the reasons why pollen, spores, and acid-resistant microscopic plant bodies are considered to be very reliable evidence and can deduce whether there was a presence of a particular person or object is the fact that different countries or even different regions of a particular country will have their unique variety of pollen and spores.

Forensic Dendrochronology: Forensic Dendrochronology implies the scientific study of estimating the growth rings of the tree to calculate the exact year in which these rings were formed. In addition to acting as evidence, the estimation of the exact year of formation of the growth ring of the tree will act as a means of determining the period in which the criminal activity may have occurred. Also, it has been noted that different species of trees have a different pattern of ring formation depending upon various factors such as the period over which the ring formation takes place, climatic conditions, amount of water present in the soil during the ring formation, etc.

Forensic Limnology: Forensic Limnology is another important and crucial branch of forensic botany that involves the examination of the presence and type of diatoms that are found on victims as well as evidence samples that are collected from the scene of the crime. Diatoms are nothing but microscopic algae with a characteristic feature of having silica in their cell wall. Diatoms can be differentiated based on various features such as their size, shape, or colour. They are never found in domestic water due to the presence of cleaning agents in them and thus are only found in freshwater. Even though there are a variety of methods for collection of this data but each one of them involves the common procedure of comparing the diatoms present at the suspected scene of the crime with that of the diatoms present in the evidence sample collected.

Forensic Plant Systematics: Plant Systematics is a branch of Forensic Botany that includes the process of classification of plants into different classes and families based on their different morphological and genetic characteristics. Thus, forensic plant systematic as the name suggests is the application of the knowledge of plant classification in solving crimes.

Forensic Ecology: Ecology is the term that is used to refer to the study of the relationship between different plant and animal species in a particular ecosystem. Thus, forensic ecology as the name suggests is the application of the knowledge of this relationship between the plant and animal species in a habitat to investigate whether the suspect could be held guilty of the crime.

APPLICATIONS OF FORENSIC BOTANY

Commonly, the application of botanical knowledge in the investigation procedure is based on two main principles. The first principle is Locard’s exchange principle which states that any contact between two objects will result in an exchange of matter between them. Thus, it can be assumed that physical evidence such as botanical trace evidence can be used to prove a link between the scene of the crime, the victim, and the criminal. For instance, the pollen grains found in a suspect’s clothes or any other belonging can be compared to the pollens found at the scene of the crime to establish a link between the scene of the crime and the suspect. The second principle is related to the use of forensic botany methods in determining the distribution of plant species around the world. This is particularly useful as different species of plants would require different environmental conditions such as soil condition, temperature, water availability, etc. and the use of this knowledge would help us to easily create a link between the crime scene, the victim, and the criminal. For instance, the presence of pollens on the corpse that are not found at the scene of crime suggests that the corpse has been moved from one place to another. 

Forensic Palynology being the most intensively developed branch of forensic botany has a very critical application in solving crimes. Pollens and spores are considered excellent evidence because of their high resistance to any extreme conditions and because they are very easily transferrable between objects pertaining to their small size. Pollens can adhere to any type of surface and due to their different shape and size can be easily identified and classified. Successful identification of species of pollens would eventually help in the determination of the place of occurrence of the crime since no two places would be having the same pollen profile. Moreover, Forensic Palynology also helps in the determination of the fact whether the corpse had been moved from one place to another after death. Palynology also helps in determining the authenticity of any particular document by analyzing the time of generation of the document with the help of pollens present on its surface.

Diatoms are another useful evidence and what adds to their value as good evidence is their occurrence throughout the year, a huge number of diatoms at a place, knowledge of their environmental occurrence, and incredible resistance to extreme conditions. Diatoms are mainly used to identify the cause, time, and place of death, especially in cases of drowning. They help in determining whether the death occurred due to drowning or the corpse was placed in the water body after death. It does so with the help of the principle that if death has occurred due to drowning, there would be asphyxiation resulting in rapid ingression of water through the respiratory tract and then through the pulmonary alveoli, thus there would be the presence of the diatoms in internal organs such as bone marrow and brain. But if the body has been placed in the water after death, the presence of diatoms would be seen only in the respiratory tract and not in any of the internal organs. Knowledge about the diatom assemblage and the comparison of the structure of assemblage of diatoms present on the suspected crime scene with that of the sample evidence helps in identifying the actual scene of occurrence.

Forensic Dendrochronology is another emerging branch of forensic botany that has great application in the determination of time since death. Estimation of the number of growth rings in the stem of various trees helps in determining the time of skeletonization of the corpse. Another use of forensic dendrochronology is in the determination of illegal logging. The government of various countries has banned the logging of certain trees as well as certain forests. The regions of the forests or trees from which the logs are obtained are determined with the help of dendrochronology.

Forensic Ecology helps in identifying any concealed or buried corpse. Whenever a corpse is concealed or buried in an ecosystem it causes structural changes in the vegetation of that area for a long time which can be easily identified. These changes help in identifying the site at which the corpse has been concealed.

The accuracy of forensic identification of various species of plants is majorly dependent on knowledge of all the above-mentioned branches of forensic botany. Physical evidence, particularly Botanical evidence should not be ignored or handled carelessly.  Even a microscopic spore may prove to be vital evidence in linking the crime scene, victim, and criminal which in turn helps in solving the crime.

CONCLUSION

Forensic Botany is a new and growing field. It still needs a lot of improvements as even today, many criminal investigators, medical practitioners, and judges are unaware of its application. This is due to the little exposure to the field of botany.

The application of the knowledge of plants into legal matters has grown constantly since the 1930s and is now one of the most important branches of forensic science. But in many parts of the world, the testimony of a forensic botanist is still not accepted. To improve the acceptability of the testimony of forensic botanists in the court of law, the expert needs to improve his/her knowledge and skills and the authorities should take necessary action to increase the awareness about the importance of forensic botany amongst people. As advancement in the field of forensics is increasing, there is the introduction of many new technologies in the branch of forensic botany as well, such as the use of DNA analysis to identify the unique traits of a particular plant species. This is a new approach but once well-developed can be utilized to prove the innocence or guilt of the suspect unambiguously.

 REFERENCES 

Coyle, Heather Miller, ed. Forensic botany: principles and applications to criminal casework. CRC Press, 2004.

Coyle, H. Miller, C. Lee, W. Lin, Henry C. Lee, and Timothy M. Palmbach. “Forensic botany: using plant evidence to aid in forensic death investigation.” Croatian Medical Journal 46, no. 4 (2005).

Aquila, Isabella, Francesco Ausania, Ciro Di Nunzio, Arianna Serra, Silvia Boca, Arnaldo Capelli, Paola Magni, and Pietrantonio Ricci. “The role of forensic botany in crime scene investigation: case report and review of literature.” Journal of Forensic Sciences 59, no. 3 (2014).

Bajerlein, Daria, Maria Wojterska, Łukasz Grewling, and Mikołaj Kokociński. “Forensic botany: current state of knowledge and possible applications in investigative practice.” Issues of Forensics Science 283 (2015).

Bandr Fakia “The branches of forensic botany”, International Journal of Development Research, 8 (2018).

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