10.15 AUSTROSTIPA S.W.L. Jacobs & J. Everett
Surrey W.L. Jacobs

Plants facultative perennials; to 2.5 m, sometimes shrublike, often with knotty bases. Culms often persistent, sometimes geniculate at the base, sometimes with stiff branches at the upper nodes; basal branching usually extravaginal; prophylls not evident. Leaves not overwintering; sheaths open to the base, margins sometimes extending beyond the base of the ligule, the extensions often conspicuously hairy, sometimes grading into the ligule; auricles not present; ligules membranous; blades flat, convolute, or terete, usually scabrous, sometimes pubescent, those of the flag leaves longer than 10 mm, bases usually as wide as the top of the sheaths, sometimes narrower. Inflorescences panicles, sometimes contracted, rachises persistent or disarticulating whole at maturity; pedicels smooth or scabrous, sometimes hairy, hairs to 3 mm; disarticulation above the glumes, sometimes also at the base of the panicle. Spikelets with 1 floret; rachillas not prolonged. Glumes usually longer than the florets, narrow, more or less keeled, hyaline to chartaceous, 1–5(7)-veined, apices usually acute or acuminate, rarely muticous or mucronate, remaining open after the floret falls; florets at least 5 times longer than wide; calluses strigose, usually sharp; lemmas usually coriaceous or indurate, 3–5(7)-veined, margins thin, usually convolute, rarely involute, apices glabrous or pilose, with 0–2 minute to small, membranous lobes, awned, lemma-awn junction evident; awns once- or twice-geniculate; paleas from shorter than to subequal to the lemmas, flat between the veins, 0–2-veined; lodicules 3 or 2; anthers 3, frequently penicillate; ovaries glabrous. Caryopses fusiform, terete; hila linear, nearly as long as the caryopses. x = unknown. Name from the Latin, austra, ‘south’, and Stipa, the name of the genus in which Austrostipa used to be included.

Austrostipa is a genus of 63 species, all of which are native to Australasia. Two species are cultivated in the Flora region.

SELECTED REFERENCE Jacobs, S.W.L. and J. Everett. 1996. Austrostipa, a new genus, and new names for Australasian species formerly included in Stipa (Gramineae). Telopea 6:579–595.

For an interactive dichotomous key, click here; the interactive, multientry key is not yet available.

1. Plants shrubby; panicle branches and pedicels plumose, hairs 1.5 mm or longer ... A. elegantissima
1. Plants bamboolike; panicle branches and pedicels not plumose, if hairy then the hairs to 0.3 mm long ... A. ramosissima

1. Austrostipa elegantissima (Labill.) S.W.L. Jacobs & J. Everett
Australian Feathergrass

Plants perennial; to 2 m, shrubby; cespitose, shortly rhizomatous. Culms decumbent, branched, with 3–6(10) nodes, glabrous. Leaves not forming a basal cluster; sheaths becoming somewhat free, glabrous, often somewhat ribbed; ligules 2–3 mm, obtuse, erose, glabrous; blades (2)5–7.5 cm long, 1.5–2 mm wide, tightly rolled, glabrous, sometimes scabrous, margins glabrous, sometimes scabrous. Panicles 14–25 cm, open, with whorls of branches bearing few spikelets, detached at maturity; branches and pedicels plumose, hairs 1.5–3 mm. Glumes 7–12 mm, 3-veined basally, veins pilose; florets 4.5–10 mm, narrowly cylindrical; calluses 0.5–0.8 mm, nearly straight, sericeous; lemmas tuberculate, mostly glabrous, black when mature, margins with short strigose hairs proximally; awns 2–5 cm, once- or twice-geniculate, first segment scabrous; paleas about 1/2 the length of the lemmas; anthers 1.5–3 mm, penicillate. Caryopses 4–5 mm. 2n = unknown.

Austrostipa elegantissima is native to southern Australia. It is cultivated as an ornamental in the United States.

2. Austrostipa ramosissima (Trin.) S.W.L. Jacobs & J. Everett
Pillar-of-Smoke, Australian Plumegrass, Stout Bamboograss

Plants perennial; to 2.5 m, bamboolike; cespitose, shortly rhizomatous. Culms 0.5–7 mm thick, erect, glabrous, with (3)6–9 nodes, highly branched at the nodes. Leaves mostly cauline, rarely basal; sheaths becoming loose, glabrous; ligules 0.2–0.5 mm, membranous, erose; blades 35–40(80) cm long, 1–10 mm wide, linear, scabrous, readily deciduous, margins scabrous. Panicles 8–20(50) cm, exserted, diffuse; branches numerous, clustering at the nodes, scabrous, glabrous, or with hairs to 0.3 mm; pedicels glabrous, scabrous, or with hairs to 0.3 mm. Spikelets 2.3–5 mm. Glumes subequal, 2.5–3 mm, erose, inflated, scabridulous, 3-veined, apices blunt or acute; florets 1.8–2.5 mm, broadly cylindrical; calluses hairy, hairs white; lemmas 1.5–2.5 mm, tuberculate, glabrous or with a tuft of silky hair; awns (14)17–30 mm, strongly once-geniculate, scabrous; paleas about 1/3 the length of the lemmas, scabrous, acute, margins glabrous; anthers 1–1.3 mm, penicillate. Caryopses (1.2)1.5–1.6 mm. 2n = unknown.

Austrostipa ramosissima is native to eastern Australia. It is cultivated in the United States and southern British Columbia. In its native range A. ramosissima is drought tolerant, but prefers moist soils and well-drained gullies near forest or woodland margins.