Lepidium bonariense

Argentine peppercress


Lepidium bonariense

L. 1753

pronounced: lep-ID-ee-um bon-ar-ee-EH-see

(Brassicaceae — the mustard family)


common name: Argentine peppercress

Lepidium is from the Greek λεπος, λεπιδος (lepis, lepidos), a (fish) scale; referring to the shape of the seed pods; bonariense is botanical Latin for ‘of or from Buenos Aires’.

This plant is a native of Brazil, northern Argentina, Paraguay and Uruguay. It is now a pan-tropical weed, and in Australia is naturalized throughout the eastern and southern parts of the country, and also on Lord Howe and Norfolk Islands. It is a common weed of crops, pastures, lawns, gardens, footpaths, parks, roadsides, disturbed sites and waste areas.

It is an annual or biennial herb that grows up to about 50 cm tall, finely hairy with weak or reflexed hairs. The basal leaves are 3 – 8 cm long, 2 – 3-pinnatisect, with the lobes up to 2 mm wide. The stem leaves reduce in size; they are pinnatifid to toothed, finely hairy, with the marginal leaves sabre-like.

The inflorescence is a dense, elongating raceme. The flowers are tiny, with sepals only about half a millimetre long, and the white petals are even shorter. There are usually 2 stamens.

The fruit is a silicula, more-or-less orbicular, 2 – 4 mm long, 2 – 3 mm wide, glabrous. Wings in the upper half form a shallow open notch.

In traditional medicine, a tincture and trituration of fresh leaves is used to treat affections of the breasts, headaches, indigestion and rheumatism. It is much used as a domestic remedy in Brazil, and is used for all the purposes that Arnica is used. All the Lepidia are anti-scorbutic, and the New Zealand species, Lepidium oleraceum, was eagerly sought after as a remedy for scurvy by the early voyagers. L. sativum is our common garden cress.

The plant is also used in homeopathic remedies, especially for anything involving numbness and stabbing pains on the left side of the body, and pain in the neck, back, and extremities.

Argentine Peppercress is a fairly inconspicuous species, and easily passes unnoticed. Confusion is most likely with Lepidium densiflorum and L. virginicum. All three have quite similar siliculae. It also bears a superficial likeness to Capsella bursa-pastoris (Shepherd’s Purse).


Information about medicinal qualities of plants, or about their use as medicines, is for interest only, and is not intended to be used as a guide for the treatment of medical conditions.


Photographs taken in Picnic Bay 2009, 2010, 2014
Page last updated 27th January 2019