Arabidopsis is a genus in the family Brassicaceae

Brassicaceae

Brassicaceae, a medium sized and economically important family of flowering plants , are informally known as the mustards, mustard flowers, the crucifers or the cabbage family....

. They are small flowering plant

Flowering plant

The flowering plants , also known as Angiospermae or Magnoliophyta, are the most diverse group of land plants. Angiosperms are seed-producing plants like the gymnosperms and can be distinguished from the gymnosperms by a series of synapomorphies...

s related to cabbage

Cabbage

Cabbage is a popular cultivar of the species Brassica oleracea Linne of the Family Brassicaceae and is a leafy green vegetable...

 and mustard

Mustard plant

Mustards are several plant species in the genera Brassica and Sinapis whose small mustard seeds are used as a spice and, by grinding and mixing them with water, vinegar or other liquids, are turned into the condiment known as mustard or prepared mustard...

. This genus is of great interest since it contains thale cress (Arabidopsis thaliana), one of the model organism

Model organism

A model organism is a non-human species that is extensively studied to understand particular biological phenomena, with the expectation that discoveries made in the organism model will provide insight into the workings of other organisms. Model organisms are in vivo models and are widely used to...

s used for studying plant biology and the first plant to have its entire genome sequenced. Changes in thale cress are easily observed, making it a very useful model.
Currently the genus Arabidopsis has nine species and a further eight subspecies recognised.