Starch Residues

Starch residues include starch grains, calcium oxalate crystals and xylem cells. Starch (carbohydrate) is the main substance of food storage for plants and is mostly found in underground stems (e.g., tubers, corms), and roots and seeds, where it is usually present as very high concentrations of grains.

Calcium oxalate crystals occur in plants as raphides (fine, sharp and needle-like) or druses (compound, more or less spherical crystals with many component crystals projecting from their surface).

Xylem is a complex vascular tissue through which most of the water and minerals of a plant are conducted, and is characterised by the presence of tracheary elements.

Many plant taxa have distinctive types of these microparts. Under the right conditions, starch residues may be preserved in soils and other deposits for long periods.