Plant materials requiring identification are encountered in a wide variety of circumstances, and these materials can be identified using a combination of PLM and phase contrast microscopy, microtomy, biological staining and autofluorescence. Microtrace staff have conducted cases, ranging from forensic to environmental to industrial, that involve questions of botanical identification. To support these projects, we maintain various reference collections of botanical materials including natural fibers, pollen, and wood. Some of these most common reference materials are also available for purchase as collections.
Natural Plant Tissues
Naturally occurring plant fragments are encountered in dusts, as contaminants in food and pharmaceuticals, and as evidence in forensic investigations. These materials can generally be classified on the basis of their morphology into a particular category (e.g., non-woody vegetable tissue, starch, woody (lignified) tissue, pollen or a particular plant structure such as a trichome). In many cases, a specific type of plant (genus and sometimes species) or a particular part of the plant may be identified.
Chars may originate from a variety of sources ranging from domestic (household) to forest fires to various industrial processes (both intentional or unintentional). In general, a char may be specifically identified as such, and in some cases (depending on the extent of charring), remaining structures may permit the source of a char to be identified. See also, combustion products and soot.
Processed vegetable matter is utilized by many industries and include food ingredients, natural fibers, vegetable drugs, paper fibers,and other cellulosic products. Specific vegetable ingredients (e.g., starch, pepper, etc.) may be identified back to a particular type of plant. In addition, the degree of processing may also be recognizable (i.e., gelatinized starch, mechanically processed pulp, optically brightened cellulose), while the presence or absence of specific plant derived chemicals, such as gluten or lignin, may be relevant to a particular legal or industrial question.