Compound grains Compound grains may be composed of >2 granules to more than 100 individual granules, for example, Festucoideae and Chloridoideae grasses. faceting A small, smooth, flat area on one or more surfaces of a starch grain which forms either through tight packing grains with a cell or as a genetic feature of the granule. fissure A long narrow opening in the starch surface, usually around the hilum. It may be a feature of the grain or a flaw caused by dehydration or chemical attack. grain The grain may be either compound or simple. granule The individual part of a compound starch grain. hilum The nucleus or center of a starch grain around which layers of starch are deposited.
Lamellae Layers of the starch grain visible under certain light conditions which reflect the structure of the grain and are comprised of alternating layers of amylose and amylopectin. raphides Needle-like crystals composed of calcium carbonate or calcium oxalate. They are found in idioblasts, which are specialized plant cells and occur in yams and tubers of some plants and can often be identified to species from their morphological features.
Simple grain Consists of a single granule and are found in many taxa in the grass subfamily Panicoideae. starch birefringence When polarized light is used to view starch granules under the microscope, the individual granules exhibit a phenomenon known as birefringence. A characteristic ‘Maltese cross’ pattern is produced by the refraction of polarized light by the intact crystalline regions in starch. usewear The examination of the used edges of tools for patterns of wear. The four features usually documented are: polish, striations, rounding, and scarring. Individually or in combination, these attributes can be used to define the task, contact material, and in some cases duration of use of the artifact.
Voucher specimen Is an identified plant specimen that serves as a basis of study and is retained as a reference, usually in a state-run herbarium (see Http://www. flmnh. ufl. edu/).