The Crossosomatales are an order, first recognized as such by

APG II The APG II system (Angiosperm Phylogeny Group II system) of plant classification is the second, now obsolete, version of a modern, mostly molecular-based, system of plant taxonomy that was published in April 2003 by the Angiosperm Phylogeny Gr ...

. They are

flowering plant Flowering plants are plants that bear flowers and fruits, and form the clade Angiospermae (), commonly called angiosperms. The term "angiosperm" is derived from the Greek words ('container, vessel') and ('seed'), and refers to those plants th ...

s included within the

Rosid The rosids are members of a large clade ( monophyletic group) of flowering plants, containing about 70,000 species, more than a quarter of all angiosperms. The clade is divided into 16 to 20 orders, depending upon circumscription and classifica ...

eudicots The eudicots, Eudicotidae, or eudicotyledons are a clade of flowering plants mainly characterized by having two seed leaves upon germination. The term derives from Dicotyledons. Traditionally they were called tricolpates or non-magnoliid dicots ...

Description

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 Gynoecium (; ) is most commonly used as a collective term for the parts of a flower that produce ovules and ultimately develop into the fruit and seeds. The gynoecium is the innermost whorl of a flower; it consists of (one or more) ''pistils' ...

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 In biology, an integument is the tissue surrounding an organism's body or an organ within, such as skin, a husk, shell, germ or rind. Etymology The term is derived from ''integumentum'', which is Latin for "a covering". In a transferred, or ...

) surrounding the

ovule In seed plants, the ovule is the structure that gives rise to and contains the female reproductive cells. It consists of three parts: the '' integument'', forming its outer layer, the ''nucellus'' (or remnant of the megasporangium), and the ...

leaves a zigzag opening (or micropyle). Some cell clusters have bundles of long yellow crystals,

mucilage Mucilage is a thick, gluey substance produced by nearly all plants and some microorganisms. These microorganisms include protists which use it for their locomotion. The direction of their movement is always opposite to that of the secretion of m ...

cells are present, and seeds have a smooth, woody coating.

Taxonomy

The relationships between orders within the Malvid clade, according to the APG system, is represented by the following tree. Within the Crossosomatales, the APG III system of 2009 recognises families represented in the following tree.

References

Angiosperm Phylogeny website
{{Taxonbar, from=Q21860 Angiosperm orders