Derivation
Rytidosperma Steud., Syn. Pl. Glum. 1: 425 (1854); from the Greek rhytis (wrinkle) and sperma (seed), referring to the back of a larva mistaken for the seed.

dimidiatum- Latin for divided down the middle. The lemma sometimes with lateral hair tufts.

Published in
New Zealand J. Bot. 17: 332 (1979).

Common synonyms
Notodanthonia dimidiata (Vickery) Veldkamp
Danthonia dimidiata Vickery

Habit
Perennial, tufted. Young shoots intravaginal. Culms erect or geniculately ascending, slender, 15–40 cm tall, 2–4-noded. Mid-culm nodes glabrous. Leaf-sheaths glabrous on surface or pilose. Ligule a fringe of hairs. Leaf-blades involute, 2–12 cm long, 1–1.5 mm wide. Leaf-blade surface glabrous or pilose.

Inflorescence
Inflorescence solid, a panicle, comprising 4–20 fertile spikelets. Panicle contracted, linear or lanceolate, 2–6 cm long. Primary panicle branches indistinct the panicle almost racemose or simple. Panicle branches puberulous or pubescent.

Spikelets
Spikelets solitary. Fertile spikelets many flowered, comprising 4–7 fertile florets, with diminished florets at the apex, cuneate, laterally compressed, 5–11 mm long, breaking up at maturity. Spikelets disarticulating below each fertile floret. Floret callus evident, pubescent.

Glumes
Glumes persistent, similar, thinner than fertile lemma, gaping. Lower glume lanceolate, 5–11 mm long, equalling upper glume, membranous, 7-nerved. Lower glume apex acute or acuminate. Upper glume lanceolate, 5–11 mm long, 150% of length of adjacent fertile lemma, membranous, 7-nerved. Upper glume apex acute or acuminate.

Florets
Fertile lemma oblong, 2.5–7 mm long, chartaceous, pallid, glossy, 9-nerved. Lemma surface villous, with 2 transverse rows of hair tufts. Lemma apex lobed, 2-fid, with lobes 2–4 mm long, setaceously acuminate, incised 50% of lemma length, 1-awned. Median (principal) awn from a sinus, geniculate, 7.5–9.5 mm long overall, with a twisted column. Column 4 mm long. Lateral lemma awns absent. Palea oblong, 2–3 mm long. Palea keels 0.8 mm apart, ciliolate, adorned above. Palea apex emarginate or obtuse. Apical sterile florets resembling fertile though underdeveloped. Lodicules 2, fleshy, ciliate. Anthers 3, 1 mm long, yellow. Grain with adherent pericarp, oblong, 1.5–1.6 mm long.

Continental Distribution:
Australasia.

Australian Distribution:
Victoria, Tasmania.

Victoria: Gippsland Plains. Tasmania: North East, West Coast, Central Highlands, Midlands, Ben Lomond, East Coast, South West.

Classification. (GPWG 2001):
Danthonioideae

Notes
Endemic. Tasmania and the southern coast of Victoria, altitude 0–1150 m, various habitats, from moorland to dry grassland, in exposed places. Flowers Dec.