Dactyloctenium aegyptium

coastal button grass


Dactyloctenium aegyptium

(L.) Willd. 1809

pronounced: dak-ty-lok-TEE-nee-um ee-jip-TEE-um

(Poaceae — the grass family)


common names: coastal button grass, crowfoot grass

Dactyloctenium is from the Greek δακτυλος (daktylos), a finger or toe, and κτεις, κτενος (kteis, ktenos), a comb, alluding to the finger-like inflorescence in which the spikelets are arranged like the teeth of a comb; aegyptium is from the Latin ægyptius, Egyptian.

This is a common weed of open ground, arable land and waste places near the sea in the tropics and subtropics of the world. In Malaysia, it is abundant in sandy soils of the lowlands and on sandy beaches near the sea. It prefers light, dry soils in Java, and grows mainly in sandy areas in the Sudan; but, despite its preference for a habitat with light soils and low moisture, it has also become an important weed in many humid tropical regions. On Magnetic Island, it is usually found on the road verges.
It is a slender to moderately robust annual grass that bends and roots at the lower nodes, forming a mat on the ground, with tips that may rise to about 70 cm in height. The roots are fibrous.

In the seedlings, the blades and sheaths are glabrous, but the leaf margins have long stiff hairs, and the ligules are fringed and membranous. As the plant grows, the blades grow up to 30 cm long and almost 1 cm wide, flat, without hairs, or, less often, having long stiff hairs. The leaf margins have hairs that point outwards. The ligule is membranous, to 1 mm long and fringed with hairs to 0.8 mm long. The sheaths are without hairs. The culms usually bend at an abrupt angle at the nodes, knee-like. The inflorescence is of 2 – 6 (usually 2 – 4) spikes, 1 – 6 cm long, ascending to radiating horizontally from the top of the culm. The lower florets have noticeable awns.

This grass reproduces mainly by seed, but also, as mentioned above, by the rooting of the stems at the lower nodes.


Photographs taken 2010, Picnic Bay
Page last updated 8th December 2018