''Phyla canescens'' is a species of

perennial A perennial plant or simply perennial is a plant that lives more than two years. The term ('' per-'' + '' -ennial'', "through the years") is often used to differentiate a plant from shorter-lived annuals and biennials. The term is also wide ...

herbaceous plant Herbaceous plants are vascular plants that have no persistent woody stems above ground. This broad category of plants includes many perennials, and nearly all annuals and biennials. Definitions of "herb" and "herbaceous" The fourth edition of t ...

in the family

Verbenaceae The Verbenaceae ( ), the verbena family or vervain family, is a family of mainly tropical flowering plants. It contains trees, shrubs, and herbs notable for heads, spikes, or clusters of small flowers, many of which have an aromatic smell. The ...

, native to South America. It has been introduced to Australia as an ornamental plant and low-maintenance lawn, but has become naturalised and is considered a serious environmental

weed A weed is a plant considered undesirable in a particular situation, "a plant in the wrong place", or a plant growing where it is not wanted.Harlan, J. R., & deWet, J. M. (1965). Some thoughts about weeds. ''Economic botany'', ''19''(1), 16-24. ...

. It is known by several common names including carpet weed, Condamine couch, Condamine curse, fog fruit, frog fruit, hairy fogfruit, lippia, mat grass and no-mow grass.

Description

''Phyla canescens'' is a much-branched, low, creeping perennial plant with wiry stems up to a metre long. The stems are often pinkish or brownish, producing adventitious roots at the joints and forming a tangled, dense mat. Older stems are grey and woody. The small, greyish-green and slightly fleshy leaves have short stalks and are in opposite pairs; the margins are either entire or have a few blunt teeth. The inflorescence is a dense, globular cluster of flowers, borne on a stalk in the axil of the leaves. The individual flowers have a short tube and five petal-like lobes, and are about long; they are white, pale pink or pale purple, with yellow centres. They are followed by small dry fruits, which remain hidden in the dried-up flower head until they split in two, when the conditions are suitable for

germination Germination is the process by which an organism grows from a seed or spore. The term is applied to the sprouting of a seedling from a seed of an angiosperm or gymnosperm, the growth of a sporeling from a spore, such as the spores of fungi, fer ...

Distribution

''Phyla canescens'' is native to South America where it has been recorded in Argentina, Bolivia, Brazil, Chile, Ecuador, Paraguay, Peru and Uruguay. It is a component of the flooding pampa grassland community. It has spread to many other parts of the world as an agricultural weed and an invasive plant. In Australia, ''Phyla canescens'' has invaded wetlands and floodplains with heavy clay soils, especially in the

Murray–Darling basin The Murray–Darling basin is a large geographical area in the interior of southeastern Australia, encompassing the drainage basin of the tributaries of the Murray River, Australia's longest river, and the Darling River, a right tributary of ...

, to the detriment of the native vegetation; the plant does best in habitats that are inundated occasionally, but can not compete with the grass ''

Paspalum distichum ''Paspalum distichum'' is a species of grass. Common names include knotgrass, water finger-grass, couch paspalum, eternity grass, gingergrass, and Thompson grass. Its native range is obscure because it has long been present on most continents, an ...

'' and the sedge ''

Eleocharis plana ''Eleocharis plana'', the flat spike-sedge, is a flat perennial sedge (in the family Cyperaceae) with creeping rhizomes, which grows up to 80 cm high in moist situations. It is widespread in inland New South Wales, and is also found in Queenslan ...

'' in more heavily inundated sites.

Ecology

''Phyla canescens'' is capable of setting seed by self-pollination but has no particular adaptations for this. In Australia, it has been found that the flowers are usually pollinated by the

honey bee A honey bee (also spelled honeybee) is a eusocial flying insect within the genus ''Apis'' of the bee clade, all native to Afro-Eurasia. After bees spread naturally throughout Africa and Eurasia, humans became responsible for the current co ...

(''Apis mellifera''), an introduced species, a non-native species like the plant itself. In the absence of honey bees, little seed is set. In Argentina, ''Phyla canescens'' has been found to be dominant in areas around plains viscacha (''Lagostomus maximus'') colonies; this seems to be because the plant's low growth habit and its lack of

palatability Palatability (or palatableness) is the hedonic reward (i.e., pleasure) provided by foods or fluids that are agreeable to the "palate", which often varies relative to the homeostatic satisfaction of nutritional, water, or energy needs. The palatabil ...

to the viscachas, which selectively feed on grasses, allows the ''Phyla canescens'' to proliferate uncontrolled. The plant also flourishes in areas with high livestock grazing pressure.

References

External links

{{Taxonbar canescens Flora of South America Taxa named by Carl Sigismund Kunth Plants described in 1899