hyssopleaf sandmat

Chamaesyce hyssopifolia
Herb
Opposite
Simple
Red
Green
Green
Discoloured

A short-lived herbaceous plant with spreading to almost upright stems usually growing up to 45 cm tall. Its slender stems contain a milky sap and are mostly hairless. Its paired leaves (5-35 mm long) are borne on very short stalks and have lop-sided bases. These leaves are light or dark green, sometimes with reddish or purplish markings, and have paler undersides. Its small 'flowers' are arranged into loose clusters in the upper leaf forks or at the tips of the branches. Its tiny hairless capsules (1.5-2.5 mm long) have three compartments, each containing a single blackish seed.

Common names 
Also known as: chicken-weed, eyebane, hyssop spurge, hyssop-leaf sandmat, hyssopleaf sandmat, spurge, wart weed,
Family 
Euphorbiaceae
Deciduous 
No
Flowering time 
Spring - Summer
Native/Exotic 
Exotic
Origin 
Native to southern USA, Mexico, Central America, the Caribbean and South America.
Notifiable 
No
Council declaration 
SIL – Special Investigation List
Known distribution 

Widely naturalised in eastern Queensland and in the coastal and sub-coastal districts of northern and central New South Wales. It is widespread in south-eastern Queensland, and particularly common in the Moreton district. It is also naturalised in the southern and central parts of the Northern Territory, in the coastal districts of Western Australia, in south-eastern South Australia, and on Lord Howe Island.

Habitat 

A weed of gardens, footpaths, lawns, nurseries, roadsides, disturbed sites, waste areas and crops.

Habit 

A small, short-lived (i.e. annual), herbaceous plant with spreading (i.e. decumbent) or semi-upright (i.e. ascending) branches usually growing 15-45 cm tall, but occasionally reaching up to 60 cm in height.

Impact and control methods 

Hyssopleaf sandmat (Chamaesyce hyssopifolia) is a common weed of gardens, crops, roadsides and disturbed sites in the region. It is sometimes encountered in natural environments in south-eastern Queensland, but is usually restricted to revegetation areas and disturbed natural vegetation. However, it has occasionally been recorded growing in more intact native vegetation (e.g. in riparian vegetation, along the margins of melaleuca swamps, in grasslands, and on coastal sand dunes).

Stem and leaves 

The stems are green, reddish or yellowish in colour and range from being hairless (i.e. glabrous) to sparsely hairy (i.e. sparsely pubescent). The stems and leaves contain a milky sap (i.e. latex). The paired leaves are simple and borne on very short stalks (i.e. petioles) only 1-2 mm long. These leaves (5-35 mm long and 2-15 mm wide) are more or less oval in shape (i.e. elliptic-oblong) or somewhat elongated (i.e. broadly-lanceolate) in shape. They have lop-sided (i.e. oblique) bases, finely toothed (i.e. serrulate) margins, and pointed or rounded tips (i.e. acute to obtuse apices). The leaves have light or dark green upper surfaces, often with reddish or purplish markings, and paler greyish-green undersides. Both leaf surfaces are initially sparsely hairy (i.e. puberulent), but they usually become hairless with age (i.e. glabrescent).

Flowers and fruits 

Tiny male and female flowers are grouped into small cup-like structures (i.e. cyathia). These greenish or reddish cyathia are produced in relatively loose clusters (i.e. cymes) the upper leaf forks (i.e. axils) or at the tips of the branches. Each cyathium consists of a small cup-like structure (i.e. involucre) 0.8-1.5 mm long with five minute teeth and four small white or pinkish petal-like appendages (i.e. glands) about 0.7 mm long. They also have 5-15 male flowers, each consisting of a single red stamen, and a single female flower, consisting of a large stalked ovary. Flowering occurs mainly during spring and summer. The tiny hairless capsules (1.5-2.5 mm long and 1.5-2.5 mm wide) have three compartments, each containing a single seed. The blackish seeds (1-1.1 mm long and about 0.8 mm wide) are four-sided, egg-shaped (i.e. ovoid) or almost rounded (i.e. globose) in shape with slightly wrinkled surfaces.

Reproduction and dispersal 

This species reproduces only by seed, which are dispersed by wind, water, vehicles, in soil and in contaminated agricultural produce.

Similar species 

Hyssopleaf sandmat (Chamaesyce hyssopifolia) is similar to asthma plant (Chamaesyce hirta) and Florida hammock sandmat (Chamaesyce ophthalmica). These species can be distinguished by the following differences: hyssopleaf sandmat (Chamaesyce hyssopifolia) has light or dark green leaves and hairless or sparsely hairy stems. Its 'flowers' (i.e. cyathia) are borne in relatively loose clusters in the upper leaf forks or at the tips of the branches (i.e. in axillary or terminal clusters) asthma plant (Chamaesyce hirta) has dark green or reddish coloured leaves and moderately to densely hairy stems. Its 'flowers' (i.e. cyathia) are borne in dense almost rounded clusters in the upper leaf forks (i.e. in axillary clusters).Florida hammock sandmat (Chamaesyce ophthalmica) has light or dark green leaves and moderately to densely hairy stems. Its 'flowers' (i.e. cyathia) are borne in dense almost rounded clusters at the tips of the branches (i.e. in terminal clusters).