Common name
Coolabah Grass

Derivation
Thellungia Stapf, Bull. Misc. Inform. 1920: 97 (1920); in honour of Albert Thellung (1881–1928), Swiss botanist.

advena- Latin for a stranger. Adventive species described from individuals found growing in countries in which they are not native

Published in
Mitt. Naturf. Ges. Soluthurn 7 (1920).

Common synonyms
Eragrostis advena (Stapf ex Probst) Phillips

Habit
Perennial, tufted. Culms erect or geniculately ascending, 60–150 cm tall. Ligule a fringed membrane or a fringe of hairs, 0.4–0.5 mm long. Leaf-blades straight, persistent, flat or involute, 10–30 cm long, 2–5 mm wide. Leaf-blade surface scaberulous.

Inflorescence
Inflorescence solid, a panicle. Panicle contracted, linear, continuous or interrupted, 20–50 cm long. Primary panicle branches appressed, bearing spikelets almost to the base. Panicle branches bearing approximate spikelets.

Spikelets
Spikelets solitary. Fertile spikelets omprising 1–5 fertile floret(s), with a barren rhachilla extension, oblong, laterally compressed, 4–5.5 mm long, breaking up at maturity. Spikelets rhachilla persistent. Spikelets disarticulating below each fertile floret, or above glumes but not between florets. Rhachilla internodes eventually visible between lemmas.

Glumes
Glumes persistent or deciduous, similar. Lower glume lanceolate, 1–2.3 mm long, 50–66% length of upper glume, membranous, 1-keeled, 1-nerved. Lower glume lateral nerves absent. Lower glume apex acute. Upper glume lanceolate, 1.8–3 mm long, equalling adjacent fertile lemma, membranous, 1-keeled, 1-nerved. Upper glume lateral nerves absent. Upper glume apex acute.

Florets
Fertile florets divergent, free at tip. Fertile lemma lanceolate, 2.5–3 mm long, hyaline or membranous, 1–3-nerved. Lemma apex acute or acuminate, muticous or pungent. Palea lanceolate, 2-nerved. Palea keels wingless, scabrous. Rhachilla extension 10% length of fertile floret. Lodicules 2, cuneate, fleshy. Anthers 3, 0.3 mm long. Stigmas 2. Grain with tardily free pericarp, laterally compressed.

Continental Distribution:
Australasia.

Australian Distribution:
Queensland, New South Wales.

Queensland: Cook, Burke, North Kennedy, South Kennedy, Port Curtis, Leichhardt, Burnett, Darling Downs, Mitchell, Warrego, Maranoa. New South Wales: North-Western Slopes, North-Western Plains, South-Western Plains, North Far Western Plains, South Far Western Plains.

Classification. (GPWG 2001):
Chloridoideae: Cynodonteae

Notes
Endemic. On heavy clay soils in association with grasslands and brigalow scrub, in swamps and disturbed alluvial flats.; flowers and fruits all year.