Common name
Hairy Spinifex
Beach Spinifex
Coastal Spinifex
Rolling Spinifex
Roly-poly
Spinifex
Spiny Rolling-grass

Derivation
Spinifex L., Mant. Pl. 2: 163 (1771); from the Latin spina (a thorn) and facere (to make), alluding to sharp pointed leaves and/or female spikelet clusters.

sericeus- from the Latin sericus (silken) and -ea (indicating resemblance). Densely invested in part or totally with long hairs.

Published in
Prodr. 198 (1810).

Habit
Perennial. Rhizomes elongated. Stolons present. Culms decumbent, 30–90 cm tall, 2–4 mm diam., woody, 5–20-noded. Mid-culm nodes glabrous. Leaf-sheaths pubescent. Leaf-sheaths outer margin hairy. Ligule a fringe of hairs, 1.8–6 mm long. Collar pubescent. Leaf-blades flat or involute, 20–40 cm long, 4–17 mm wide, rigid. Leaf-blade surface pubescent. Leaf-blade margins smooth. Leaf-blade apex acuminate, muticous. Dioecious.

Inflorescence
Inflorescence digitate, with racemose branches, terminal and axillary, subtended by a spatheole, embraced at base by subtending leaf. Spatheole expanded, lanceolate, scarious. Racemes 1, radiating, unilateral, 12–17 cm long, bearing 1 spikelet (at the base). Rhachis subterete, scabrous on surface, pubescent on surface, terminating in a barren extension, extension subulate (quill-like, spinous), extension 120–170 mm long. Spikelet packing abaxial.

Spikelets
Spikelets appressed, solitary. Male spikelets sessile. Fertile spikelets 2-flowered, comprising 1 fertile floret, without rhachilla extension, lanceolate, dorsally compressed, acute or acuminate, 12–18 mm long, falling entire, deciduous with accessory branch structures. Spikelet callus pubescent.

Glumes
Glumes similar, firmer than fertile lemma. Lower glume lanceolate, 12–18 mm long, 100% of length of spikelet, membranous or chartaceous, 7–11-nerved. Lower glume surface glabrous or puberulous to pubescent. Lower glume apex acuminate. Upper glume lanceolate, 12–18 mm long, 100% of length of spikelet, membranous or chartaceous, 7–9-nerved. Upper glume surface glabrous or puberulous to pubescent. Upper glume margins eciliate or ciliate. Upper glume apex acuminate.

Florets
Basal sterile floret 1, without significant palea. Lemma of lower sterile floret similar to upper glume, lanceolate, 9–15 mm long, 100% of length of spikelet, chartaceous or cartilaginous, 5–9-nerved, prominently nerved, smooth or scaberulous, rough on nerves, eciliate on margins or ciliate on margins, acuminate. Fertile florets female. Fertile lemma lanceolate, 7–15 mm long, membranous. Lemma apex acuminate. Anthers 6–7 mm long. Disseminule comprising a synflorescence. Secondary disseminule an inflorescence. Male inflorescence unlike female (racemes 2–3cm long bearing 5–8 spikelets), a single raceme (in a compound capitulum). Male spikelets distinct from female, 2-flowered, lanceolate, 8–15.5 mm long, hairy. Male spikelet glumes 2, 7–10-nerved.

Continental Distribution:
Australasia.

Australian Distribution:
South Australia, Queensland, New South Wales, Victoria, Tasmania.

South Australia: Nullabor, Northern Lofty, Yorke Peninsula, Southern Lofty, Kangaroo Island, South-eastern. Queensland: Cook, North Kennedy, South Kennedy, Port Curtis, Wide Bay, Moreton. New South Wales: North Coast, Central Coast, South Coast. Victoria: Wannon, Otway Plain, Otway Range, Gippsland Plains, Wilsons Promontory, East Gippsland. Tasmania: King Island, Furneaux Group, North West, North East, East Coast.

Classification. (GPWG 2001):
Panicoideae: Paniceae

Notes
Native, coastal, often on dunes, also in New Zealand. Flowers Nov.–Jan. in SE Australia and June–Aug. in Qld.
The male inflorescence of this species is similar to that of Spinifex hirsutus.