Bidens pilosa

Bidens pilosa is commonly called Black jack, beggarticks, sweethearts, muuwu, nhungunisa (Shona), ucucuza (Ndebele). It is native to the tropical Americas, but has spread and is very widely naturalised throughout the tropics and subtropics. Stories are that in Vietnam it was called Soldier's food as it was so often eaten by them. ^[1]

Description

Annual herb growing to 1.5m. Stems square. Leaves generally three leaflets. Flowers small creamy white daisies with yellow centres. Fruit, black, with barbed bristles that catch in fur and clothing.

There is a related plant, Bidens biternata, the Yellow flowered blackjack. ^[2] ^[3]

Preparation / Uses

Leaves - preferably young shoots, are boiled (as one would spinach). The leaves can also by dried for later use.
Fruits (the black jacks) - boil one portion of seeds with two portions of water. Cool. drain liquid, mix about 4 to 1 with more water, and use as spray to keep insects off other edible plants.

Recipes

Lightly boil, and when soft, add peanut butter and mix. Salt. Serve as relish.

Health / Medicinal

It is reported to treat various diseases and infections, commonly rheumatism, diarrhoea, ear, eyes and tooth ache problems.

Chew the young shoots to relieve rheumatism.
Use the juice for sore eyes or ears.
Fresh leaves can be made into a poultice on sores. Or infused as colic remedy.
Powdered leaf can be mixed with water and used as an enema.
Flower is used as part of a diarrhoea remedy.

On the basis of the present investigation, we propose that the leaf extract of B. pilosa might be a good candidate for the search of efficient environment friendly natural bioactive agent and pharmaceutically important compounds.

^[4]

However, the roots, leaves and flowers are strongly phototoxic. Substances isolated from the leaves can kill human skin in the presence of sunlight at concentrations as low as 10ppm. Consumption of the leaves, as in South Africa, has been found to promote the development of oesophageal cancer.