Crossosomatales

Species assigned to the Crossosomatales have in common flowers that are positioned solitarily, with the base of the calyx, corolla, and stamens fused into a tube-shaped floral cup, sepals overlapping, the outermost smaller than the inner. Insides of the casings of pollen grains have horizontally extended thin regions (or endo-apertures). The gynoecium is placed on a short stalk, papillae on the stigma consist of two or more cells, ovary locules 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 coating.^[2]

The relationships between orders within the Malvid clade, according to the APG system, is represented by the following tree.^[3]

Within the Crossosomatales, the APG III system of 2009 recognises families represented in the following tree.^[4]

• Angiosperm Phylogeny website