foetid cassia

Senna tora
Herb
Alternate
Compound
Yellow
Green

The Senna tora is an herbaceous annual foetid herb. The plant can grow 30–90 centimetres (12–35 in) tall and consists of alternative pinnate leaves with leaflets mostly with three opposite pairs that are obovate in shape with a rounded tip. The leaves grow up to 3–4.5 centimeters long. The stems have distinct smelling foliage when young. The flowers occur in pairs in axils of leaves with five petals and pale yellow in colour. The stamens are of unequal length. The pods are somewhat flattened or four angled, 10–15 cm long and sickle shaped, hence the common name sickle pod. There are 30–50 seeds within a pod.

Common names 
Also known as: Chinese senna, Java bean, Java-bean, low senna, peanut weed, sickle senna, sicklepod, sicklepod senns, stinking cassia, wild senna,
Family 
Caesalpiniaceae
Deciduous 
No
Native/Exotic 
Exotic
Origin 
India/ S.E.Asia.
Notifiable 
No
State declaration 
Category 3 - Must not be distributed or disposed. This means it must not be released into the environment unless the distribution or disposal is authorised in a regulation or under a permit.
Council declaration 
As per State Declaration
Known distribution 

This species has a scattered distribution in the coastal and sub-coastal regions of northern Queensland and the northern parts of the Northern Territory. It has also been recorded in coastal central Queensland.

Habitat 

A weed of disturbed sites, waste areas, roadsides, waterways, plantation crops and pastures in wetter tropical and sub-tropical environments.

Habit 

A small short-lived (i.e. annual or biennial), upright (i.e. erect), shrub usually growing 50-150 cm tall, but sometimes growing up to 2.5 m in height.

Impact and control methods 

This species can invade and completely dominate pastures and other disturbed areas such as roadsides, fence lines, creek banks and disturbed areas. They have the potential to become major weeds of many crops within a matter of two or three growing seasons. Sicklepod and sennas are unpalatable to domestic stock. However, cattle and horses will eat mature seed, which can pass through the animal and germinate in dung.

Stem and leaves 

The branched, sprawling, stems are usually hairless (i.e. glabrous) or sparsely hairy (i.e. puberulent).
The compound (i.e. pinnate) leaves are alternately arranged along the stems and are borne on relatively long stalks (i.e. petioles) 20-45 mm long. These leaves (50-75 mm long) have two to four pairs of leaflets that are egg-shaped in outline with the narrower end attached to the stalk (i.e. obovate). The leaflets (10-55 mm long and 10-35 mm wide) have rounded tips (i.e. obtuse apices) and their margins are lined with tiny hairs (i.e. cilia). There is a small elongated structure (i.e. gland) usually located between each of the lowest two pairs of leaflets (sometimes these glands are only present between the lowest pair of leaflets). The leaves of this species give off a strong unpleasant odour, particularly when damaged or brushed against.

Flowers and fruits 

The yellow flowers are borne on short stalks (i.e. pedicels) 6-10 mm long. These flowers are arranged in pairs in the leaf forks (i.e. axils) and are mostly found near the tips of the branches. Each flower has five sepals, five yellow petals (8-10 mm long) and seven fertile stamens with small anthers (1.5-2.5 mm long). Flowering occurs mostly from late summer through to early winter.
The fruit is a very slender, sickle-shaped (i.e. falcate), pod (12-25 cm long and 2-6 mm wide) that is almost round in cross-section (i.e. cylindrical) and curved downwards. These pods turn brownish-green as they mature and are slightly indented between each of the numerous (20-30) seeds (i.e. the pods are faintly septate). The seeds are striped olive and brown (about 3 mm long), shiny in appearance, and flattened (i.e. compressed) or irregularly shaped (i.e. rhombic-rounded).

Reproduction and dispersal 

This plant reproduces by seed which are dispersed by water and animals that eat the fruit (e.g. cattle). They may also be spread as a contaminant of agricultural produce (i.e. fodder and pasture seeds) or in mud sticking to animals, footwear, machinery and vehicles.

Similar species 

This species is very similar to sicklepod (Senna obtusifolia), hairy senna (Senna hirsuta), coffee senna (Senna occidentalis), smooth senna (Senna septemtrionalis) and the native arsenic bush (Senna planitiicola). It is also relatively similar to Easter cassia (Senna pendula var. glabrata) and pepper-leaved senna (Senna barclayana).