Brassicaceae.
The Mustard or Cabbage family was previously known as Cruciferae.
Plants of the World Online (Kew) recognises 346 genera while others 274 to 375 with around 3000 to 4000 species
distributed around the world.
The family includes well known food plants such as cabbage, radish and broccoli as well as ornamentals that include Alyssum,
Lobularia, Lunaria and Matthiola (stocks).
Almost all are herbs with occasional shrubs and lianas (woody vines).
The annual, biennial or perennial plants have a taproot or sometimes a woody above and/or below ground caudex that may be a
storage structure such as a tuber or rhizome.
Stems can be erect, or prostrate with or without an erect tip.
Simple and variously branched hairs are present but none are glandular.
Leaves may be basal in a rosette and/or alternate in a spiral along a stem.
With or without a petiole that may be winged, they vary greatly in size.
The mostly simple blades are entire or variously deeply dissected especially towards the base of the plant.
A few species have once divided (pinnate) leaves.
The edges are smooth or have blunt (dentate) or sharp teeth (serrate).
There may be two glands at the petiole base and simple, branched or stellate hairs.
Inflorescences are almost always a cluster of variously arranged flowers.
They can be terminal, axillary or leaf opposed.
The bisexual flowers are on a pedicel that may have glands at the base.
The 4 almost always free sepals are in pairs at right angles to each other (decussate).
The inner pair may have a short basal sac or spur that stores nectar.
Occasionally there are no petals but most have 4 white, orange, yellow, purple, pink or blue ones.
Often with a claw base they are in 2 decussate whorls forming a cross when seen from above.
Up to around 1 cm long they can be wide or narrow with a round, pointed or notched tip.
The receptacle (top of the pedicel holding the flower parts) almost always has a nectiferous or hypogynous disc that
may be a ring or divided into lobes (nectaries).
The lobe number, shape, size and position in relation to the stamens varies but there is always one on either side of the
2 outer stamen filaments.
There are typically 6 stamens with 2 (the laterals) in the outer whorl and 4 longer ones in the inner whorl.
The filaments are mostly free of each other and the basifixed anthers open inwards through longitudinal slits.
The filaments may have an appendage.
The superior ovary, of 2 fused carpels has 2 locules often divided by a false septum.
On the receptacle or a short stalk (gynophore), each chamber has one to many ovules usually with parietal placentation and in 1 or 2 rows.
The 1 or 2-lobed stigma is on a short style or attached to the ovary.
Fruit take various forms but are often capsules that may have a short beak and no to dense hairs.
The variously shaped, typically yellow or brown seeds may have a wing.
J.F.
