African boxthorn is a large shrub which grows up to 5 metres high and is covered in spines. The leaves are oval in shape and are 10–40 millimetres long and 4–10 millimetres in width. The flowers appear either singly or in pairs at the leaf-stem junction. They are white or pale lilac with a lilac-purplish throat and are about 1cm in diameter, 5 petalled and fragrant. The calyx (the sepals of one flower collectively) is 4-7mm long and has 5 unequal teeth. The flowers are 10-12mm long with the 5 stamen projecting to 2- 4mm past the petals. The flowers appear mostly in summer but there is also some flowering throughout the year.
The fruit is a berry that is smooth and shiny with a short drooping stalk. It is globose (ball-shaped) to broad-ovoid shaped and is 5-10mm in diameter with a prominent calyx. The berry ripens to a dull orange-red colour with up to 35-70 seeds. The seeds are 2.5mm long by 1.5mm wide ovoid or irregular in shape and flattened. They are light brown to yellow and dull with small raised dots on the surface.
African boxthorn was introduced into Australia from South Africa in the mid 1800s and was commonly used as a hedge plant. It has become an aggressive invader of pastures, roadsides, reserves, remnant bushland and waterways. It forms an impenetrable, spiny thicket that inhibits the movement of stock and provides a haven for feral animals. Many insects, including fruit fly, the common house fly and the tomato fly, breed in the fruit of this weed.
African boxthorn is toxic to humans and will cause discomfort and irritation, but is not life-threatening. The berries, leaves, stems and roots are all poisonous, and can cause nausea, vomiting, breathing difficulties and unconsiousness.
This post is part of the Floral Friday Fotos meme,
and also part of the Weekend Green meme.