Foraging in Johannesburg

Know these first

What can hurt you around Johannesburg in October

4 species on our hazard list have been recorded near here this month, 1 of which can kill a healthy adult. Learn these before you learn anything you intend to eat.

• Can kill75 records nearby

  Ragworts and groundsels (Senecio)

  Senecio (the whole genus)

  Mistaken for

  Wild greens and herbal teas — and, in the past, home-grown wheat: Senecio in the flour poisoned whole families in South Africa's George district in 1918.

  How to tell

  Daisy-family plants with yellow flower heads (with or without petals), each head wrapped in a single row of narrow green bracts, often black-tipped, and seeds carrying white fluffy parachutes. A yellow daisy you can't name does not go in the pot.

  What it does

  Pyrrolizidine alkaloids, which baking does not destroy. They block the small veins of the liver (veno-occlusive disease): pain, a swollen liver and fluid in the belly, and in many cases cirrhosis. Children are the most vulnerable.

• Hospital22 records nearby

  Lantana (tickberry)

  Lantana camara

  Mistaken for

  Blackberry-like clusters of small dark berries that children pick; it smothers forest edges, roadsides and farmland across East and southern Africa.

  How to tell

  A scrambling shrub with square, prickly stems, rough leaves that smell sharp when crushed, flat clusters of tiny flowers that change colour as they age (yellow to orange, pink or red), and tight bunches of small berries ripening green to glossy purple-black.

  What it does

  The green, unripe berries are the dangerous ones: vomiting, diarrhoea and difficulty breathing have been reported in people. Livestock that eat the leaves suffer liver damage and severe sunburn.

• Hospital19 records nearby

  Syringa (chinaberry)

  Melia azedarach

  Mistaken for

  Children pick up the berries under the trees: it is planted for shade and has run wild in South Africa, where it is called syringa.

  How to tell

  A tree with large, twice-divided leaves of toothed leaflets, sprays of fragrant lilac flowers in spring, and smooth, round, marble-sized berries that turn yellow and hang on the bare branches through winter.

  What it does

  Neurotoxins concentrated in the fruit: vomiting, bloody diarrhoea, confusion and convulsions a few hours after eating. Poisoning has followed as few as six to nine fruits.

• Hospital17 records nearby

  Euphorbias (milk bushes, naboom, pencil tree)

  Euphorbia (the whole genus)

  Mistaken for

  Prickly pear and other cacti — many African euphorbias are spiny, leafless succulents that look exactly like cacti — and the pencil-stick hedges of Euphorbia tirucalli around farms and villages.

  How to tell

  Break a stem: a euphorbia bleeds white milky latex at once. Cacti such as prickly pear bleed clear or slimy sap, and their spines grow from small fuzzy cushions; euphorbia spines grow singly or in pairs, never from a cushion.

  What it does

  The latex burns skin and mouth, and in the eye can cause temporary blindness. Wear gloves and eye protection near a cut plant, and never rub your eyes.

These are recorded within about 40 km of here in this month, from verified public observations. It is not a complete list of what is dangerous — nothing is — and a species missing from it may still be in your woods. Never eat anything identified from a photograph and a description alone.