Plants, in particular the model plant Arabidopsis thaliana,
fulfill the above mentioned requirements. A classical attempt
to describe the organization of the body of higher plants,
including Arabidopsis, relies on the concept of phytomers. A
phytomer is a repetitive unit that consists of a leaf, a leaf
attachment site including an axillary bud (nodium) and an
associated piece of stem (internodium) (Gaudichaud, 1841;
Gray, 1849). The variation of plant shoot morphology between
most, if not all, higher plant species can be understood by
considering it as the phylogenetic and ontogenetic modification of this fundamental unit.