Heteropogon triticeus  (R.Br.) Stapf ex Craib 1912

pronounced: het-er-oh-POH-gon trit-ih-KEY-uss

(Poaceae —  the grass family)

common name: Giant Spear Grass

Heteropogon heteropogon triticeusgiant spear grassheteropogon triticeusis derived from the Greek 'ετερος (heteros), different, and πωγων (pogon), beard, referring to the awned and awnless spikelets; triticeus is Latin for ‘of wheat’, referring to the appearance of the seed heads.

Heteropogon is a small genus of annual and perennial grasses known generally as ‘tangleheads’. They are erect tussock grasses found in tropical regions world-wide, and some species grow in warmer temperate areas as well. The inflorescences hold paired spikelets. The lower pairs are equal in size, and the upper pairs include one awned bisexual spikelet and one awnless sterile spikelet.

Heteropogon triticeus is a perennial from a tough rootstock. The culms are stout, erect, and hard, 1–3 m tall. The leaf sheaths are keeled and fan-shaped at the plant base, glabrous or with minute stiff hairs; the leaf blades are flat and stiff, 30–60 by 0.4–0.8 cm, glabrous to hairy, the apex acuminate; the ligule very short. The inflorescence is a terminal raceme, sometimes with a few axillary racemes below it. The racemes (excluding the awns) are 8–15 cm, with  5–11 awns, each with 12–15 pairs of infertile spikelets below the awned fertile pairs. The spikelets are dark brown at maturity; the callus about 6 mm, pungent, densely brown-bearded; the lower glume linear-oblong, deeply grooved on either side of the midrib; the awns 9–16 cm, brown, the column shortly pubescent. The pedicelled spikelets are 1.5–2 cm, the lower glume oblong-lanceolate, green, laterally asymmetrically winged, and glabrous.

heteropogon triticeusheteropogon triticeusWhere the grass is found mixed with other species in the tropical grasslands of northern Australia, it is grazed to a certain extent by beef cattle. In some areas, it appears that the indigenous people harvested the seeds and ground them to make flour.

There are many areas of the giant spear grass, usually growing among other species, on Magnetic Island.

Lepidoptera larvae that feed on this grass include the Evening Brown Melanitis leda and the Dingy Bush-brown Mycalesis perseus.

 Photographs taken 2010, Picnic Bay, on the slopes of Hawkings Point

Page last updated 11th December 2016

 

 

 

 

 

 

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