- Any of various clump-forming, perennial Australian grasses, chiefly of the genus <em>Triodia,</em> growing in arid regions and having awl-shaped, pointed leaves.
- In Australia, any one of several species of grasses having stiff, sharp-pointed leaves or spiny flower-clusters, especially the two following, distantly related species: <em>Spinifex hirsutus</em>, the hairy spinifex or spiny rolling-grass. See under <internalXref urlencoded="rolling-grass">rolling-grass</internalXref>.
- <em>Triodia irritans</em>, the desert spinifex, more often called <internalXref urlencoded="porcupine-grass">porcupine-grass</internalXref>. See <internalXref urlencoded="porcupine-grass">porcupine-grass</internalXref>, 2.
- A genus of chiefly Australian grasses, the seeds of which bear an elastic spine. <spn>Spinifex hirsutus</spn> (black grass) and <spn>Spinifex longifolius</spn> are useful as sand binders. <spn>Spinifex paradoxus</spn>is a valuable perennial fodder plant. Also, a plant of this genus.
- Any of several Australian grasses of the genus Tricuspis, which often form dense, almost impassable growth, their leaves being stiff and sharp-pointed.
- An <xref>Australian</xref> <xref>coastal</xref> <xref>grass</xref> in genus Spinifex