Phytolith
Definition
Opaline silica body precipitated in or between plant cells during growth. Grass phytoliths are produced in high quantities and persist in soil after plant death because opaline silica is chemically resistant to most soil conditions.
- Composition
- Opaline silica (a form of silicon dioxide)
- Persistence
- Chemically resistant, survives in soil and sediment long after plant material decays
- Scale
- Microscopic (visible only under magnification)
Common questions
What exactly is a phytolith?+
A phytolith is a tiny silica body that forms inside or between plant cells as the plant grows. After the plant dies and decays, these silica particles remain in the soil and sediment for a very long time because silica resists most soil conditions.
How do phytoliths help in forensic investigations?+
Phytolith assemblages (groups of them) can reveal what plants lived in a particular area at a particular time. This helps reconstruct past vegetation types and plant communities, which can link evidence to geographic locations or help date sediment layers.
Why are grass phytoliths especially useful?+
Grasses produce phytoliths in very high quantities. Since these opaline silica particles are highly resistant to decay and soil chemistry, grass phytoliths accumulate in large numbers and create distinctive patterns that are easier to identify and analyze.
Related terms
- Acetolysis
- Erdtman's 1934 extraction method. The sample is treated with a 9:1 mixture of acetic anhydride and concentrated sulphuric acid, which dissolves cellulose...
- Caryopsis
- The grain of a grass: a single-seeded fruit in which the seed coat is fused to the ovary wall. Shape, size, and...
- Diatom frustule
- The siliceous cell wall of a diatom, composed of biogenic opal; species-specific in shape and ornament, and resistant to degradation in soil...
- Floret
- The basic reproductive unit of a grass spikelet, consisting of the lemma, palea, and the enclosed flower. Floret morphology, including lemma surface,...
- Lemma
- The lower of the two bracts enclosing the grass floret. Its surface texture, venation, awn character, and marginal features are major identification...
- Morphotype
- A phytolith shape class defined by the geometry of the silica body: bilobate, cross-shaped, saddle-shaped, elongate, dendritic, and so on. Individual morphotypes...
- Palynomorph
- Any acid-resistant microscopic organic particle recovered by palynological processing, including pollen grains, spores, dinoflagellate cysts, and fungal spores. Each type carries different...
- Soil micromorphology
- The preparation of undisturbed soil blocks as resin-impregnated thin sections for examination under a polarising light microscope, revealing the microstructure, particle composition,...
- Subfamilies Panicoideae and Chloridoideae
- Two of the major grass subfamilies. Panicoideae (warm-season C4 grasses of humid tropics and subtropics) are characterised by bilobate and cross-shaped phytoliths....
- Terminus post quem (TPQ) from artefacts
- The date of the youngest datable artefact in a sealed context, which sets the earliest possible date for the sealing event. A...
Explained in these topics
- Finds and Artefact ProcessingA microscopic silica body formed inside or between plant cells, which persists in soil and sediment after the plant has decayed. Phytolith assemblages can iden...
- Grass and Grass Phytolith AnalysisOpaline silica body precipitated in or between plant cells during growth. Grass phytoliths are produced in high quantities and persist in soil after plant deat...