Definition and significance of floral diagrams

A floral diagram is a schematic cross-section, preferably through a young flower in which all the individual organs or elements of the flower are projected into one plane. A floral diagram is the best way to show the number and topological properties of floral organs. Different parts of the flower are represented by clear symbols, and the spaces between organs are an approximate reflection of the distance between the organs. Fusions between different parts are shown by connecting lines, and the orientation of the flower by placing reference points in relation to the axis of the inflorescence and the subtending bracts. Floral diagrams have two major attributes: (1) the information that can be retrieved from a good floral diagram is immense and replaces extensive descriptions or even drawings, and (2) they facilitate a whole-scale comparison of floral structures across the angiosperms. An inconvenience is that it is concentrated on a limited number of characters at the expense of others that do not fit on the diagrams. Endress (2008a) discussed the benefits of accurate drawings over detailed descriptions. A floral diagram is a clearer way to convey information, as a synthesis of the details of flowers.

There are different ways to create floral diagrams. These range from a simplified drawing of the position of organs in the flower in relation to each other, to a very complex representation of details that cannot always be seen without a lens.