''Digitaria didactyla'' is a species of

grass Poaceae () or Gramineae () is a large and nearly ubiquitous family of monocotyledonous flowering plants commonly known as grasses. It includes the cereal grasses, bamboos and the grasses of natural grassland and species cultivated in lawns an ...

known by the common names blue couch, Queensland blue couch, blue serangoon grass, green serangoon grass, blue stargrass, and ''petit gazon'' (in

Mauritius Mauritius ( ; french: Maurice, link=no ; mfe, label=Mauritian Creole, Moris ), officially the Republic of Mauritius, is an island nation in the Indian Ocean about off the southeast coast of the African continent, east of Madagascar. It incl ...

).Cook, B. G., et al
''Digitaria didactyla''.
Tropical Forages. CSIRO, DPI&F (Qld), CIAT and ILRI, Brisbane, Australia. It is native to Mauritius,

Réunion Réunion (; french: La Réunion, ; previously ''Île Bourbon''; rcf, label= Reunionese Creole, La Rényon) is an island in the Indian Ocean that is an overseas department and region of France. It is located approximately east of the island ...

, parts of mainland Africa, and

Madagascar Madagascar (; mg, Madagasikara, ), officially the Republic of Madagascar ( mg, Repoblikan'i Madagasikara, links=no, ; french: République de Madagascar), is an island country in the Indian Ocean, approximately off the coast of East Africa ...

.''Digitaria didactyla''.
Grassland Species Profiles. FAO. It has been introduced widely outside its native range, mainly for use as a

pasture Pasture (from the Latin ''pastus'', past participle of ''pascere'', "to feed") is land used for grazing. Pasture lands in the narrow sense are enclosed tracts of farmland, grazed by domesticated livestock, such as horses, cattle, sheep, or swine ...

and

turf Sod, also known as turf, is the upper layer of soil with the grass growing on it that is often harvested into rolls. In Australian and British English, sod is more commonly known as ''turf'', and the word "sod" is limited mainly to agricultu ...

grass. It has

naturalized Naturalization (or naturalisation) is the legal act or process by which a non-citizen of a country may acquire citizenship or nationality of that country. It may be done automatically by a statute, i.e., without any effort on the part of the in ...

in some regions.

Description

This species is a mat-forming perennial grass with

rhizome In botany and dendrology, a rhizome (; , ) is a modified subterranean plant stem that sends out roots and shoots from its nodes. Rhizomes are also called creeping rootstalks or just rootstalks. Rhizomes develop from axillary buds and grow hori ...

s and

stolon In biology, stolons (from Latin '' stolō'', genitive ''stolōnis'' – "branch"), also known as runners, are horizontal connections between organisms. They may be part of the organism, or of its skeleton; typically, animal stolons are external s ...

s. The stems can reach up to 63 centimeters long,''Digitaria didactyla''.
Grass Manual. Flora of North America. but are generally 15 to 30 centimeters, with a creeping form, extending along the ground and rooting at the stem nodes.Clayton, W. D., et al. (2006 onwards)

GrassBase - The Online World Grass Flora. Accessed 20 June 2013. The narrow leaf blades are up to 7 centimeters long, usually hairless, and green to blue-green in color. The

inflorescence An inflorescence is a group or cluster of flowers arranged on a stem that is composed of a main branch or a complicated arrangement of branches. Morphologically, it is the modified part of the shoot of seed plants where flowers are formed o ...

has 2 to 4 thin, finger-like branches each up to 7 to 10 centimeters long. They are lined with pairs of small spikelets each under 3 millimeters long. The grass can grow into a dense, leafy stand up to 20 centimeters tall unless it is kept down, for example, with

grazing In agriculture, grazing is a method of animal husbandry whereby domestic livestock are allowed outdoors to roam around and consume wild vegetations in order to convert the otherwise indigestible (by human gut) cellulose within grass and other ...

. This species is similar to

southern crabgrass ''Digitaria ciliaris'' is a species of grass known by the common names southern crabgrass,''Digitaria ...

(''Digitaria ciliaris''), but with fewer, narrower inflorescence branches. It is also similar to

bermudagrass ''Cynodon dactylon'', commonly known as Bermuda grass, is a grass found worldwide. It is native to Europe, Africa, Australia and much of Asia. It has been introduced to the Americas. Although it is not native to Bermuda, it is an abundant invasiv ...

(''Cynodon dactylon''), but with shorter, wider leaves which are more blue in color.

Biology

This grass can tolerate many soil types, including low-nutrient and low- pH substrates, but it does best in lighter soils. It thrives in

granitic A granitoid is a generic term for a diverse category of coarse-grained igneous rocks that consist predominantly of quartz, plagioclase, and alkali feldspar. Granitoids range from plagioclase-rich tonalites to alkali-rich syenites and from quart ...

sands. It is somewhat tolerant of shade and occasional flooding. It usually persists in dry conditions, but it may drop its leaves.

Frost Frost is a thin layer of ice on a solid surface, which forms from water vapor in an above-freezing atmosphere coming in contact with a solid surface whose temperature is below freezing, and resulting in a phase change from water vapor (a gas) ...

shrivels the leaves. The grass is very tolerant of grazing and mowing. A rhizomatous and stoloniferous species, it spreads easily via

vegetative reproduction Vegetative reproduction (also known as vegetative propagation, vegetative multiplication or cloning) is any form of asexual reproduction occurring in plants in which a new plant grows from a fragment or cutting of the parent plant or spec ...

. It also produces seeds, which can be spread in the dung of grazing cattle and remain viable in the soil. Though it does not necessarily require

fertilizer A fertilizer (American English) or fertiliser (British English; see spelling differences) is any material of natural or synthetic origin that is applied to soil or to plant tissues to supply plant nutrients. Fertilizers may be distinct from ...

, the grass responds well to supplemental nitrogen. Good companion plants include

legume A legume () is a plant in the family Fabaceae (or Leguminosae), or the fruit or seed of such a plant. When used as a dry grain, the seed is also called a pulse. Legumes are grown agriculturally, primarily for human consumption, for livestock f ...

s such as three-flower beggarweed (''Desmodium triflorum''), glycines (''Glycine'' spp.), pinto peanut (''Arachis pintoi''), Australian jointvetch (''Aeschynomene falcata''), Brazilian stylo (''Stylosanthes guianensis''),

lotononis ''Lotononis'' is a genus of flowering plants in the family Fabaceae and the tribe Crotalarieae. Almost all of the species in the genus occur in southern Africa. Species Several species were recently transferred from ''Lotononis'' to four new or ...

(''Lotononis bainesii''), round-leaf cassia (''Chamaecrista rotundifolia''), and

white clover ''Trifolium repens'', the white clover, is a herbaceous perennial plant in the bean family Fabaceae (otherwise known as Leguminosae). It is native to Europe, including the British Isles,Clapham, A.R., Tutin, T.G. and Warburg., E.F. 1968. ''Excursi ...

(''Trifolium repens''). Pathogens seen in this grass include grey mould and the digitaria striate mosaic virus, a

mastrevirus ''Mastrevirus'' is a genus of ssDNA viruses, in the family ''Geminiviridae''. Mostly monocotyledonous plants serve as natural hosts. They are vectored by planthoppers. There are 45 species in this genus. Diseases associated with this genus inclu ...

of the family

Geminiviridae ''Geminiviridae'' is a family of plant viruses that encode their genetic information on a circular genome of single-stranded (ss) DNA. There are 520 species in this family, assigned to 14 genera. Diseases associated with this family include: bri ...

which is transmitted by the

leafhopper A leafhopper is the common name for any species from the family Cicadellidae. These minute insects, colloquially known as hoppers, are plant feeders that suck plant sap from grass, shrubs, or trees. Their hind legs are modified for jumping, and a ...

'' Nesoclutha pallida''.Lapierra, H. and P. A. Signoret. ''Viruses and Virus Diseases of Poaceace (Gramineae).'' Editions Quae. 2004. pg. 755.CBrunt, A. A., et al. (Eds.) (1996 onwards)
Digitaria striate mosaic monogeminivirus.
Plant Viruses Online. Version: 20 August 1996. Pests include

spider mite Spider mites are members of the Tetranychidae family, which includes about 1,200 species. They are part of the subclass Acari (mites). Spider mites generally live on the undersides of leaves of plants, where they may spin protective silk webs, a ...

s of genus ''

Oligonychus ''Oligonychus'' is a genus of mites in the family spider mite, Tetranychidae, the spider mites. Many members of this genus are familiar pest (organism), pests of plants. There are about 200 described species.Walter, D. E''Oligonychus''.Invasive M ...

''.

Uses

This species has long been used as a pasture grass for grazing

livestock Livestock are the domesticated animals raised in an agricultural setting to provide labor and produce diversified products for consumption such as meat, eggs, milk, fur, leather, and wool. The term is sometimes used to refer solely to animals ...

. Animals find it palatable. It is also planted as a

lawn A lawn is an area of soil-covered land planted with grasses and other durable plants such as clover which are maintained at a short height with a lawnmower (or sometimes grazing animals) and used for aesthetic and recreational purposes. L ...

and used as

golf course A golf course is the grounds on which the sport of golf is played. It consists of a series of holes, each consisting of a tee box, a fairway, the rough and other hazards, and a green with a cylindrical hole in the ground, known as a "cup". Th ...

turf. It is thought to be "one of the most popular lawn grasses in Queensland." It may be used as other forms of

groundcover Groundcover or ground cover is any plant that grows over an area of ground. Groundcover provides protection of the topsoil from erosion and drought. In an ecosystem, the ground cover forms the layer of vegetation below the shrub layer known as t ...

. It is very good for

erosion control Erosion control is the practice of preventing or controlling wind or water erosion in agriculture, land development, coastal areas, river banks and construction. Effective erosion controls handle surface runoff and are important techniques in ...

Cultivar A cultivar is a type of cultivated plant that people have selected for desired traits and when propagated retain those traits. Methods used to propagate cultivars include: division, root and stem cuttings, offsets, grafting, tissue culture, ...

s include 'Aussiblue' and 'Tropika', grey-green grass breeds recommended for turf use.''Digitaria didactyla'' 'Aussiblue'.
The State of Queensland. Department of Natural Resources and Mines. 2012.''Digitaria didactyla'' 'Tropika'.
The State of Queensland. Department of Natural Resources and Mines. 2012.

Swazi grass

''Digitaria swazilandensis'' (swazi grass, Swaziland fingergrass) is sometimes considered to be a

subspecies In biological classification, subspecies is a rank below species, used for populations that live in different areas and vary in size, shape, or other physical characteristics (morphology), but that can successfully interbreed. Not all species ...

of ''D. didactyla''.Heuzé V., Tran G., Hassoun P., 2016. Swazi grass (Digitaria swazilandensis). Feedipedia, a programme by INRA, CIRAD, AFZ and FAO. https://www.feedipedia.org/node/454 Last updated on September 10, 2016, 0:04 Other authorities treat it as a species in its own right, but it has similar uses to ''D. didactyla''. It is coarser in texture, bulkier, and less blue in color. Its stolons are less robust but it produces less seed and spreads vegetatively more often. It is more tolerant of

soil salinity Soil salinity is the salt content in the soil; the process of increasing the salt content is known as salinization. Salts occur naturally within soils and water. Salination can be caused by natural processes such as mineral weathering or by the ...

and more resistant to diseases.

References

{{Taxonbar, from=Q13906170 didactyla Grasses of Africa Flora of Madagascar Flora of Mauritius Flora of Réunion Flora of Southern Africa Forages Lawn grasses Plants described in 1809