Flickweed (bittercress)
Cardamine hirsuta

There is a common misconception that foraging in the winter is hard, with a scarcity of species variety available, and smaller growth. So does winter have much to offer the wild food forager? In my opinion, it sure does. In the colder months of South East Australia, you can still get a great variety of plants. Yummy, nutritious wild edibles that prefer the colder days and nights, and flourish in winter. There is a whole set of botany that you will only find at this time of the year and many that are actually at their very best when we are rugging up to brace for the cold.
Species like chickweed, mallow, dandelion and flatweed all do well in winter, offering plenty of new, juicy leaves, just before they start to flower and seed.

One such wonder is flickweed, a small, inconspicuous plant of the Brassica family who, right now, in July, is everywhere. Lucky us, it is also delicious, with a slight peppery flavour, excellent raw in salads or sandwiches, or if you collect enough, cooked in soups and pies. Yay for winter greens!

How to identify flickweed

A Brassica family herb (related to cabbage, broccoli, mustard, canola, rocket, bokchoi, etc). Like many of the family (see other wild brassica here), it is a short-lived annual that forms a rosette or ring of leaves ( see images below).  When in a good position it can grow to a height of 30 cm and spread as wide.  The stem is erect and the leaves are green and imparipinnate, meaning they have a central stalk from which 3-9 leaflets appear in opposite pairs, with a bigger one at the very top.  The flowers are pale mauve and small, only about 1-3mm wide and typical of the family, have 4 petals. 
The flowers occur in clusters at the ends of branches, followed by little bean-like fruits, 15-25 mm long pods, which are narrow and erect.  They are about 1-2 mm thick.  The seeds are tiny, brown and with a smooth coat. 
The interesting feature of this small edible is that the seedpods explode when ready. That’s right, when the seedpods are fully mature, they harness a propelling power so that if you touch them, the seeds explode all around, hence the name, flickweed. This seed dispersal strategy is referred to as ballochory and is a type of rapid plant movement.

It is fun to go around the garden and brush the flowering heads of this plant with your hand, to trigger this incredible explosion of seeds. Its a great nature game for kids and kids at heart!

Distribution

You will find this plant all over South-East Australia, see map, from north of Brisbane to Adelaide, plus Tasmania and South-West Western Australia. You will see plenty of flickweed in disturbed environments with damp soil. It is extremely common in nurseries, under the propagation trays, where it gets regular irrigation and succeeds in withstanding constant weeding. If you live within the areas displayed on the map, check your garden, as is surely there.

How to eat flickweed

The whole plant is edible, but leaves and flowers are the most used. In the colder months, it has lots of leaves at the base that can get up to 10cm long. These are slightly peppery (think rocket), and a great addition to your salads and sandwiches. A few leaves here and there add a nice spicy flavour to your meals. If you collect enough, you could use them in soups, pesto or pies. The plant germinates most freely in autumn and leaves are usually available all winter. My wife is a big fan of using edible flowers to make dishes look great and, while many of the usuals like nasturtiums and violets are hard to come by on wintry days, the lovely little white/mauve flowers of flickweed are plentiful.

Notes: 

The plant is also known as bittercress, but I do not find it bitter at all.
In Old English the plant is known as stune, and is cited as one of the herbs invoked in the pagan Anglo-Saxon Nine Herbs Charm, recorded in the 10th century.
'Stune' is the name of this herb, it grew on a stone,
it stands up against poison, it dashes against poison

Further readings:

Wikipedia on flickweed > wikipedia.org/wiki/Cardamine_hirsuta
Atlas of Living Australia on flickweed> bie.ala.org.au