Australian Tropical Rainforest Plants - Online edition

Mirabilis jalapa L.


Weed
Herb (herbaceous or woody, under 1 m tall)
Shrub (woody or herbaceous, 1-6 m tall)
Click/tap on images to enlarge
Leaves and Flowers. © CSIRO
Scale bar 10mm. © CSIRO
10th leaf stage. © CSIRO
Family

Linnaeus, C. von (1753) Species Plantarum 2: 177. Type: Habitat in India utraque.

Common name

Common Four-O'clock; Marvel-of-Peru; Four-o'clock

Stem

Flowers and fruits as a shrub about 1-2 m tall.

Leaves

Leaf blades about 3-9 x 2-3.5 cm, rather thin and papery. Short tortuous hairs present on the upper surface along the midrib and major lateral veins. Lateral veins forming loops inside the blade margin. Petiole channelled on the upper surface. Twigs slightly swollen above each pair of leaves. Twig surfaces mainly smooth except for two bands of short tortuous hairs on opposite sides of the twigs.

Flowers

The structure of the flowers is rather confusing. What appears to be a green calyx is actually green floral bracts. What appears to be the corolla is actually a corolliform calyx. Perianth to about 6.5 cm long, limb about 2.5-3.5 cm diam. All stamens are of different lengths, anthers +/- reniform. The ovary is surrounded and enclosed by five fleshy aristate scales which are probably the reduced petals. Stigma comparatively large and tuberculate.

Fruit

Fruits globular, about 7-8 mm long, longitudinally ribbed. Testa thin and papery. Endosperm granular or powdery. Embryo on the margin of the seed, the cotyledon margin recurved and surrounding the endosperm.

Seedlings

Cotyledons about 20-25 x 30-45 mm, wider than long. At the tenth leaf stage: leaf blade triangular or cordate, apex acuminate. Petiole grooved on the upper surface. Taproot thick and dark, carrot-shaped (Daucus carota). Seed germination time 68 days.

Distribution and Ecology

An introduced species originally from Peru, now naturalised in NEQ and south-eastern Queenslands and southwards as far as south eastern New South Wales. Altitudinal range in NEQ from near sea level to 750 m. Usually found as a garden escapee but grows in disturbed rain forest on the Atherton Tableland.

Natural History & Notes

This species is slightly poisonous. If ingested it causes stomach pain and vomiting. If the roots are handled they can cause dermatitis. (http://www.ces.ncsu.edu/depts/hort/consumer/poiso n/Mirabja.htm (17-8-2000)).

Roots leaves and seeds poisonous. Austin, D. F. 1998. Poisonous Plants of Southern Florida. (http://www.fau.edu/divdept/science/envsci/poison- pl.html)

This species may have medicinal properties and it is also poisonous. (http://squid2.laughingsquid.net/hosts/herbweb.com /herbage/A17339.htm)

RFK Code
3468
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