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Dactyloctenium radulans (R.Br.) P.Beauv. 1812
(Poaceae – the grass family)
common name: Native Button Grass
Dactyloctenium is from the Greek δακτυλος (daktylos), a finger or toe, and κτενιον (ktenion), a little comb; radulans is from the Latin radula, a scraper – one look at the seed head will tell you why.
The Button Grasses all have digitate inflorescences in which the spikelets have a comb-like arrangement. They may be annuals or perennials, rhizomatous or stoloniferous or tufted or decumbent. Some are native, others naturalized. Although they are sometimes found in saline habitats or dunes, they are mostly found in dry sandy soils. They all produce a prolific quantity of small distinctive seeds, about 1 mm long.
The seedlings of Native Button Grass are erect, but the plants become prostrate as they become larger. The leaves are 2–5 mm in width and about 5 cm in length. The ligule is a low, papery rim, only about 0.5 mm wide, capped with hairs. The adult leaves grow anything up to 12 cm long, and are 2–6 mm at the base, tapering to the tip. When the plants are mature, we have a short, sprawling summer-growing annual grass with stems to 20 cm long, and without stolons.
The seed heads, which clearly distinguish this grass from its cousin the Coastal Button Grass, consist of tight bands of 3–10 spikes 5–12 mm long, forming compact globular heads at the ends of the stems. The seeds are 1 mm long and light brown, with a very rough seed coat and a short beak above the embryo.
Plants emerge rapidly after the first rains of the wet season, and quickly produce new seed. This grass is generally a short-lived annual, but in frost-free areas can become perennial, given sufficient moisture. In drier outback areas it is a useful pasture grass, especially on the lighter soils. Button grass will grow in fields and along ditches and roadsides. It is not highly competitive, due to its prostrate nature, but can sometimes become a pest. As can be seen in the photograph, these plants were competing, not very successfully, with Alyce Clover.
This species is native to Australia, and is distributed widely in inland areas throughout all the mainland states. It is mainly in cultivated areas of central Queensland that it is considered a nuisance in crops. It usually occurs near the coast, and on off-shore islands, only in the tropics.
Photographs taken 2010, Picnic Bay - Nelly Bay Road
Page last updated 11th November 2016