Common name: Button Grass
Gymnoschoenus sphaerocephalus (R.Br.) Hook.f. APNI*
Description: Big tussock-forming perennial. Culms terete or somewhat compressed, striate but smooth, glabrous, often 1 m or more high, 1–2.5 mm diam.
Leaves with blade often 50 cm long, 1–2.5 mm wide; sheath striate but shining, greyish yellow-brown.
Inflorescence 1.5–2 cm diam.; involucral bracts usually 3, broad and sheathing at base, to about as long as inflorescence. Glumes obovate to broad-elliptic, glistening, yellow-brown, papery with thinner wavy, erose margin; lowest 3 or 4 glumes ± broad-oblong, much shorter than upper; uppermost 3 glumes 5–5.5 mm long, the lowest of these 3 closely enveloping the other 2 much narrower glumes. Bristles somewhat longer than nut, usually remaining with inflorescence. Anthers 2.5–3 mm long; apical appendage 0.3–0.7 mm long.
Nut (rarely collected) obovoid to broad-ellipsoid, 3.0–3.5 mm long, 1.6–1.8 mm diam., the loose outermost layer grey-brown, sparsely hispidulous at apex and base of style or glabrous; the inner nut c. 2.5 mm long with shining, slightly wrinkled and minutely reticulate, pale red-brown surface.
Distribution and occurrence: Coast south from Myall Lakes, and Tablelands south from Gibraltar Range to the Robertson area.
Grows in permanent swamps and on wet slopes.
NSW subdivisions: NC, CC, SC, NT, CT, ST
Other Australian states: Vic. Tas. S.A.
In the Blue Mtns, in the Clarence-Newnes area, there is a form that differs in having long awns (2-3 mm long) on the lowest sterile glumes. These glumes also differ in being acute and scattered-pubescent, while the involucral bracts are long-ciliate at the top of the broad base and have a blade that is up to twice as long as the inflorescence Culm striations are usually more prominent in this form, and the glumes and nuts are somewhat longer.These differences do not seem sufficient to recognize this as a separate species.
Text by K. L. Wilson
Taxon concept: Flora of NSW 4 (1993)
APNI* Provides a link to the Australian Plant Name Index (hosted by the Australian National Botanic Gardens) for comprehensive bibliographic data
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