*Brassica nigra, showing the typical Brassicaceae flower
2. *B. nigra,showing the typical Brassicaceae inflorescence
3. Lepidium pseudotasmanicum
4. L. pseudotasmanicum, with minute flowers without petals
5. Rorippa nasturtium-aquaticum
* introduced species
Brassicaceae is a large family of herbs that is represented in Tasmania
by about 21 native species and about 47 introduced species. Species
occur in almost all open habitats. The leaves are alternate or in
a basal rosette. The flowers are relatively distinctive. They occur
in terminal racemes and each has four free petals that are often spreading
in a cross-shape (hence the family's old name) and usually six stamens.
The fruit is dry, usually a specialised capsule called a siliqua.
The variation in the form of the fruit is important in identifying
Many of the Brassicaceae are difficult to identify, and the key
may be ambiguous for some species.