Sporobolus indicus (L.) R.Br.

Code

SPZIN

Growth form

Grass

Life cycle

Vivacious

Habitat

Terrestrial

Global description

Sporobolus indicus is a grass in dense tufts, rhizomatous, sometimes more than 1 m high. Cylindrical, smooth culm, 2 to 5 mm in diameter. Leaves linear, dark green 6 to 20 cm long and 0.3 to 0.5 cm wide ending in a fine point. Glabrous sheath, ligule reduced to a short ciliate membrane. False-eared spike erect 6-20 cm long and 4-7 mm in diameter; the linear ramifications are applied along the axis. The spikelets are green to simple brownish, small (2 mm) and extremely numerous overlapping each other. The glumes are of unequal length and are usually 1 mm long. The flower usually has three stamens. The fruits are grains of a length of 1 mm. Morphological variations are numerous.

 

New Caledonia: The seeds of Sporobolus indicus germinate at the beginning of the rainy season; young plants grow rapidly and produce seeds again, then slow their growth in the cool, dry season.

Sporobolus indicus is a vivacious cespitose grass that multiplies vegatatively by short rhizomes and by its seeds whose production is very important (up to 2 million seeds per hectare) but the majority of which are dormant (more than 2 years old) or not viable. They become sticky at maturity and are thus transported on the animals' coat, their hooves, clothing and farm machinery.

Characters to distinguish some Sporobolus spp.

Size	Inflorescence	Branches	Spikelet	Glumes	Species
90-160 cm	Spike-like with spreading branches	5-10 cm	1,7-2 mm	Subequal Gl inf 0,2-0,6 mm Gl sup 0,5-0,8 mm GL sup < 1/3 L épillet	Sporobolus pyramidalis
30-100 cm	Spike-like, narrow with appressed branches	1-2 cm	1,8-2 mm	Slightly different Gl inf 0,6-1 mm Gl sup 0,9-1,3 mm 1/3 < Gl sup < 2/3 L spikelet	Sporobolus indicus
30-110 cm	Spike-like, narrow with appressed branches	1-2 cm	2,1-2,8 mm	Very different Gl inf 0,4-0,7 mm Gl sup 1-1,5 mm 1/2 < Gl sup < L spikelet	Sporobolus africanus
10-60 cm	Diffuse panicle		1-1,5 mm	Subequal Gl inf 0,4-0,6 mm Gl sup 0,6-1 mm 1/2 < Gl sup < L spikelet	Sporobolus festivus

Origin

Sporobolus indicus is a native species of Central and South America

Worldwide distribution

This species has been introduced in Western Europe, Madagascar, South Asia, Eastern Australia, New Caledonia and the Pacific Islands.

Overall harmfulness

Sporobolus indicus is one of 300 major invasive species in tropical Australia, the Indian Ocean and Oceania including New Caledonia where it has been introduced for a long time (first specimen seen in 1855).

Local harmfulness

New Caledonia: The seeds of  Sporobolus indicus being largely transported by animals, the first infestations are observed along the roads, tracks and on the path of herds for which this species is very unattractive and of low fodder value. It is even reported that its fibrous nature can cause tooth loss in cattle and horses. The regrowths of less than one month are however consumed. Large stands produce large quantities of dead biomass favoring fire starts. On pasture, it remains relatively infrequent.

New Caledonia: Slashing with rotary cutters is made difficult on Sporobolus indicus that is a very fibrous grass. Done after fruiting, it can also strongly contribute to the spread of the highly prolific species by its seeds. Still young individuals can be removed manually with the entire root system. In larger flooding situations, the use of herbicide treatment after slashing if possible and before seed production is a good control but should be repeated considering the seed bank present in the soil. Note that glyphosate is not very effective. It will be preferred other active ingredients such as hexazinone, 2,2-dpa, amitrol + atrazine, flupropanate

Herbarium pictures ReCOLNAT: https://explore.recolnat.org/search/botanique/simplequery=Sporobolus%2520indicus