Brassicaceae (Cruciferae)
Dilleniidae: Capparales. The Brassicaceae are herbs or rarely subshrubs
comprising about 350 genera and 3,000 species. The leaves are alternate or rarely opposite
and typically are simple but sometimes have deeply parted segments; stipules are lacking.
The flowers are bisexual and almost always actinomorphic. The perianth consists of a calyx
of 4 distinct sepals and typically a corolla of 4 distinct petals that are commonly clawed
and diagonally disposed. The androecium is tetradynamous, consisting of 4 long inner
stamens and 2 short outer stamens. The gynoecium consists of 2 carpels that are generally
separated by a persistent false partition called a replum. The superior ovary is usually
2-loculed and bears few to many ovules on parietal placentae. At maturity, the 2 valves of
the fruit typically separate, leaving the ovules attached to the persistent replum. Long,
narrow fruits of this family are called siliques, short broad ones are called silicles.
Each "thumbnail" image below is linked to a larger photograph.
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Raphanus sativus, wild radish. The cross-shaped configuration of
the flowers in this family resulted in its early designation as the Cruciferae. The style
with its small capitate stigma can be seen just above the anthers. Long, narrow fruits of
this family such as that seen in this photo are called siliques. In the photo on the right
the yellow anthers of four long stamens and two short stamens can be seen. This condition
of the stamens is described as tetradynamous, and is typical for the family. Also visible
here is the typical narrow greenish claw at the base of each petal. |
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Lobularia maritima, sweet alyssum. Note the typical 4-parted
perianth, the androecium of 4 long and 2 short stamens, and the capitate stigma. |
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Capsella bursa-pastoris, shepherds purse. In this family, short
broad fruits such as these are called silicles. At maturity the two valves of siliques and
silicles separate from the persistent replum or false partition. A few seed stalks or
funiculi can still be seen attached to the edge of some of the persistent partitions. |
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Iberis umbellata, candytuft. This genus is unusual in the family in
having the corolla somewhat zygomorphic, with two petals larger than the other two. |
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