Phytoliths are biomineralizations present in cell walls and/or inter or intracellular spaces of plant tissues. Although the term "phytolith" refers to different amorphous and/or mineral deposits compounded by different elements, such as calcium or silicon, this book focuses on amorphous biogenic silica (SiO2.nH2O), also known as opal phytoliths, silica phytoliths or silicophytoliths. In the present chapter a review of phytolith production and functions, organ and tissue localization and distribution among plant families is presented. It also describes the main phytolith morphologies found in plants, soils and sediments and their taxon assignment. The taxonomic value of these amorphous silica biomineralizations and the classifications employed in different phytolith studies are also discussed. A summary of some phytolith indexes, used in palaeoenvironmental studies from different regions and based on the relative abundances of morphologies, is presented. Lastly, applications and limitations of phytolith studies are mentioned.

Fil: Osterrieth, Margarita Luisa. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; Argentina

Fil: Fernández Honaine, Mariana. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; Argentina

Fil: Gomes Coe, Heloisa Helena. Universidade Federal do Estado do Rio de Janeiro; Brasil