Datura.
Family Solanaceae > Subfamily Solanoideae > Tribe Datureae.
Devil’s trumpets are from Central and South America.
Various authors accept from 9 to 14 species and there are many synonyms.
Classification is difficult because some species are very similar and they can be very variable.
Grown as ornamentals the 5 species naturalised in Australia are weeds.
They are herbs or small shrubs up to 2 m high sometimes with purple stems.
Young branches may have dense simple hairs with or without glands.
The hairs may be lost on older branches and sometimes young ones have no hairs.
The solitary leaves are alternately arranged in a spiral.
On petioles up to 8 cm long the blade can be from 5 to 20 or 25 cm long.
They are ovate to lanceolate, wide or narrow and may have a wavy margin.
The tip is blunt or pointed and the sometimes asymmetric base round or heart-shaped.
The edge can be smooth or have pointed or rounded lobes or teeth.
Young leaves are often densely hairy, especially on the veins but become hairless with age.
The mostly axillary but sometimes terminal flowers are almost always solitary.
Initially erect they later become horizontal.
They are on stalks (pedicels) up to 1 cm long that may have hairs.
The tubular, funnel or trumpet-shaped flowers are from 5 to 20 cm long.
The narrow calyx tube is up to 8 cm long with 5 (3 to 9) triangular lobes up to 2.5 cm long.
There may be a few hairs on it.
The narrow corolla tube is up to 20 cm long with a flaring top up to 10 cm across.
The upper margin may be just wavy with slight indentations.
Other flowers have 5 (or up to 10 with 5 shorter) triangular teeth or lobes.
The lobes usually curve back and the tips may have an almost linear extension up to 1.5 cm long.
In the bud the petals are folded and twisted.
Flowers are typically single although doubles may be occasionally be seen.
Cultivars can have double or triple corollas.
They are usually white and may be variously coloured in purple or yellow.
The 5 stamens are inserted into the lower half of the corolla tube.
They are of equal length and do not extend beyond the corolla.
There are short white hairs on the filaments below the point of insertion.
The linear, baisfixed anthers, up to 17 mm long open inwards via long slits.
The superior ovary has 2 locules but may have 4 at the base due to false septa.
The numerous ovules have axile placentation.
The style is up to around 1.5 cm long with a bilobed appearing stigma.
The fruit is a roundish to ovoid capsule up to 4 cm long.
The surface has a few to many blunt tubercles or pointy spines up to 8 mm long.
Brown or purplish when ripe it splits irregularly at the top into 2 or 4 chambers.
The calyx lobes fall off and the tubular part develops a projecting rim up to 1.5 cm across.
The flattened, brown seeds are ovate or D-shaped with a thickened, ridged edge.
J.F.
