Spinifex grass

Spinifex sericeus, commonly known as hairy spinifex, rolling spinifex, beach spinifex or coastal spinifex, is a dioecious perennial grass native to Australia and New Zealand. It has branched stolons and rhizomes extending up to several metres. The leaves have a ligule of a rim of dense hairs; the blades are flat and densely silky. The male inflorescence is an orange-brown terminal cluster of spiky racemes subtended by silky bracts. The female inflorescence detaches at maturity, a globose seed head of sessile racemes up to 20 cm in diameter which becomes a tumbleweed. It is an important pioneer species which colonises coastal dunes, binding loose sand with its horizontal runners (wiki)
It was spotted in Owhiro Bay, Wellington NZ.