Aristida gracilipes

three-awn speargrass


Aristida gracilipes

(Domin) Henrard 1926

pronounced: ar-RISS-ti-duh gra-SILL-ih-peez

(Poaceae — the grass family)


common names: three-awn speargrass, wiregrass

native 4Aristida is from the Latin arista, an awn; gracilipes is from two Latin words, gracilis, slender, and pes, a foot. This is a member of the Wiregrass genus of tufted annual or perennial grasses.

This species is perennial, and clumped loosely, growing about 60 – 115 cm tall, the culms geniculately ascending. The mid-culm internodes are glabrous. Lateral branches tend to be more-or-less parallel to the main stem. The leaf-sheaths are smooth or scaberulous, glabrous on the surface. The ligule may bear a fringe of hairs, about 0.5 mm long. The leaf-blades are straight, conduplicate or involute, or convolute, 4 – 8 cm long, 0.5 mm wide. The leaf-blade is scabrous.

The inflorescence is compound, a linear panicle 12 – 21 cm long and 1 – 3 cm wide.

The spikelets are pedicellate. The fertile spikelets are single-flowered, lanceolate, terete, 8 – 11 mm long.

The glumes are thinner than the fertile lemma. The lower glume is lanceolate, membranous and keeled, with mucronate apex. The upper glume is also lanceolate, 4 – 10 mm long, membranous and keeled, the apex entire, or erose, or mucronate.

In the florets, the fertile lemma is 8 – 11 mm long, without a keel, 3-nerved. The lemma apex is 3-awned. The median (principal) awn is without a column.

The reader may know of the Wiregrass Country, a region of the USA encompassing parts of southern Georgia, south-eastern Alabama, and the Florida Panhandle. It is named for the wiregrass Aristida stricta, which is native to the region, and widespread there.

Wiregrasses provide ground cover even on the poorest soils where few other grasses will grow. They are often indicators of overgrazed pastures, as they are palatable only when very young. Overgrazing reduces or eliminates more desirable species, allowing the wiregrasses to increase. They are generally low-yielding, producing little leaf, which is usually shed in times of stress.

Aristida perniciosa is a native of Australia, occurring down most of the Queensland coast. The stand photographed is near the lookout at the top of the ‘steps’ track at the north of Picnic Bay. The plant flowers and fruits from January to July.


Photographed in Picnic Bay 2010
Page last updated 12th October 2018