Common name
Serrated Tussock
Yass Tussock

Derivation
Nassella (Trin.) Desv., in C.Gay, Fl. Chil. 6: 263 (1854); from the Latin diminutive of nassa (a narrow-necked wicker basket), referring to the shape of the floret of some South American species.

trichotoma- from the Greek trika (three-fold) and tomos (piece). Inflorescence branches produced in threes.

Published in
Anales Mus. Nac. Montevideo 1: 336 (1896).

Common synonyms
Stipa trichotoma Nees

Habit
Perennial, densely tufted. Culms 30–60 cm tall. Leaf-sheaths smooth, glabrous on surface. Ligule an eciliate membrane, 0.5–2.5 mm long, truncate or obtuse. Leaf-blades filiform, convolute, 15–45 cm long, 0.2–0.5 mm wide, coriaceous.

Inflorescence
Inflorescence compound, a panicle, exserted or embraced at base by subtending leaf. Panicle open, ovate, effuse, 8–25 cm long. Panicle branches capillary.

Spikelets
Spikelets solitary. Fertile spikelets 1-flowered, comprising 1 fertile floret, without rhachilla extension, lanceolate, terete, 4–8.5 mm long, breaking up at maturity. Spikelets disarticulating below each fertile floret. Floret callus evident, pilose, acute, hairs 50% of length of lemma.

Glumes
Glumes persistent, similar, thinner than fertile lemma. Lower glume lanceolate, 4–8.5 mm long, equalling upper glume, hyaline, 3-nerved. Lower glume surface scabrous. Lower glume apex acuminate or attenuate. Upper glume lanceolate, 4–8.5 mm long, 250–350% of length of adjacent fertile lemma, hyaline, 3-nerved. Upper glume surface scabrous, rough on nerves. Upper glume apex acuminate or attenuate.

Florets
Fertile lemma oblate, laterally compressed, 1.5–2.5 mm long, coriaceous, lightly keeled. Lemma surface tuberculate. Lemma margins convolute, covering most of palea. Lemma apex truncate, surmounted by a distinct coma of hairs (obscure), 1-awned. Median (principal) awn eccentric, geniculate, 15–35 mm long overall, with a twisted column, persistent or deciduous. Column glabrous. Palea 50% of length of lemma, hyaline, 0-nerved, without keels. Anthers 3, 1–1.5 mm long. Grain with adherent pericarp, oblong, 1.2 mm long, dark brown.

Continental Distribution:
Europe, Africa, Australasia, South America.

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

South Australia: Murray. New South Wales: Central Coast, South Coast, Northern Tablelands, Central Tablelands, Southern Tablelands, Central-Western Slopes, South Western Slopes. Victoria: Midlands, Victorian Volcanic Plain, Otway Plain, Gippsland Plains. Tasmania: King Island, East Coast.

Classification. (GPWG 2001):
Pooideae: Stipeae

Notes
Introduced. Weed of pastures, unpalatable to stock.