The species assigned to the Crossosomatales have in common that the flowers are positioned solitary, with the base of the calyx, corolla, and stamens fused into a tube-shaped floral cup, the sepals overlapping, with the outermost smaller than inner ones. The inside of the casings of the pollen grains have horizontally extended thin regions (or endo-apertures). The gynoecium is placed on a short stalk, the papillae on the stigma consist of two or more cells, the ovarylocules taper upwards, and the protective cell layer (or integument) surrounding the ovule leaves a zigzag opening (or micropyle). Some cell clusters have bundles of long yellow crystals, mucilage cells are present, and seeds have a smooth, woody seed skin.
Within the Crossosomatales, the APG III system of 2009 recognises the families that are represented in following tree, which is based the most recent insights in the relationships within the Crossosomatales.