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Site Menu Ecology and Systematics |
Location of Clandestine Graves | Identification of Controlled Substances |
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Forensic analysis often requires the identification of botanical evidence to species. Ecological knowledge of plant species is useful to investigators in two main ways: to determine whether plant fragments recovered from a victim or object came from where it was found or from some other area (Lane et al., 1990), and in locating clandestine graves (Bock and Norris, 1997). Systematic expertise is required when the identity of suspected drug species, notably marijuana, is in question (Lane et al., 1990). |
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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 soon colonize the site, followed by later-succession species and finally, the climax assemblage of species. The change in species composition of a site can be predicted to some extent for some geographical locations and habitat types. If a certain localized site shows a different successional stage than the surrounding area, this is an indication of a potential burial site. Disturbances in vegetation can be identified more than twenty years after the event. |
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Many controlled substances are derived from plants; e.g. marijuana (Cannabis sativa L.), opium poppy (Papaver somniferum L.) and peyote (Lophophora williamsii) (Bock and Norris, 1997). Particularly in the case of marijuana, expert identification is required due to the phylogenetic controversy surrounding the Cannabis genus (Lane et al., 1990). There are several cultivars of marijuana; some systematists consider the Cannabis genus to be monotypic, while others think it is polytypic. The "species defense" was popular in the 1960s and 70s in states that declared only Cannabis sativa L. to be illegal; defense attorneys claimed that their clients were not growing Cannabis sativa L. but some other cultivar, and would have experts from the "polytypic" camp to testify on their behalf. Prosecutors, on the other hand, would get monotypists to declare that all Cannabis was Cannabis sativa L. In the United States, |
Marijuana, Cannabis sativa L. var. indica. Photo by Jocelyn Peña, courtesy of Southwest School of Botanical Medicine. |
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there is still not a consensus on the issue, but the laws are more specific: in some states, any plant belonging to the genus Cannabis is considered to be marijuana, other states list species in addition to Cannabis sativa L., and still others consider all marijuana to be Cannabis sativa L. by legislative fiat (Lane et al., 1990). |
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palynology | anatomy and dendrochronology | ecology and systematics | molecular biology The Forensic Botany site was created in 2002 by Jennifer Van Dommelen as a project in the Web Literacy For the Natural Sciences class at Dalhousie University, Halifax, Canada. Terms in bold are defined within the body of the text. Highlighted terms and author citations are linked to a glossary and reference list, respectively, which open in new windows. All images have been used with permission. Header banners created by Jennifer Van Dommelen. Last content update: April 2002 Contact: | ||||
