The history of the plant embryo. Terminology and visualization from ancient until modern times

Since ancient times comparisons between embryonic forms of humans, animals, and plants are known. In deciphering a plant embryo and its development, one applied a specific zoomorphic terminology. Until the 17th century naturalists who studied plants were inspired by the concepts of ancient natural philosophy. Since then plant embryos are visualized by drawings and diagrammatic sketches. In the 18th century the embryo became an important issue in debates concerning theories of generation and the analogy between animal egg and vegetable seed was emphasized. Due to the cell theory and refined microscopic techniques around 1850 botanists described the 'plant embryo' as an aggregate of cells. The 20th century profited of further technical improvements, e.g. microphotography, SEM, and plant tissue culture. The spell of the word embryo integrated morphological and morphogenetic data in botany and served as a code to decipher botanic forms. The paper presents a short history of the concept of 'plant embryo' and focuses on its distinct meanings over centuries, supported by different images.