Common name
Button Grass
Finger Grass

Derivation
Dactyloctenium Willd., Enum. Pl. 1029 (1809); from the Greek daktylos (finger) and ktenion (a little comb), alluding to the digitate inflorescences.

radulans- from the Latin radula (scraper) and -ans (assuming the form of). Leaf-blades scabrid.

Published in
Ess. Agrostogr. 72, 160 (1812).

Habit
Annual or ephemeral, tufted. Stolons absent. Culms erect or geniculately ascending or decumbent or prostrate, 7–40 cm tall. Mid-culm internodes striate, smooth, glabrous. Mid-culm nodes glabrous. Lateral branches branched. Leaf-sheaths loose, striately nerved, glabrous on surface. Ligule a fringed membrane, 0.5 mm long. Leaf-blades tapering towards tip, 4–8 cm long, 3–4 mm wide. Leaf-blade margins tuberculate-ciliate, hairy at base. Leaf-blade apex acuminate.

Inflorescence
Inflorescence digitate, with spicate branches. Spikes (3–)4–7(–10). Spikes closely spaced. Spikes in a head. Spikes erect or ascending, unilateral, 0.5–1.5 cm long, 3.5–5 mm wide. Spikes erect or ascending. Rhachis deciduous from axis, flattened, terminating in a barren extension, extension subulate. Spikelet packing broadside to rhachis, imbricate, regular, 2-rowed.

Spikelets
Spikelets pectinate, solitary. Fertile spikelets many flowered, comprising 2–4 fertile florets, with diminished florets at the apex, ovate or obovate, laterally compressed, 3–5 mm long, breaking up at maturity. Spikelets disarticulating above glumes but not between florets.

Glumes
Glumes persistent, dissimilar. Lower glume ovate, 1–2 mm long, 70–80% length of upper glume, membranous, 1-keeled, 1-nerved, midnerve scabrous. Lower glume lateral nerves absent. Lower glume apex acute. Upper glume elliptic or oblong, 1.5–3 mm long, equalling adjacent fertile lemma, membranous, 1-keeled, 1-nerved, midnerve smooth. Upper glume lateral nerves absent. Upper glume apex acute, awned. Upper glume awn 0.5–2.5 mm long.

Florets
Fertile florets appressed to rhachilla. Fertile lemma 2.5–3.5 mm long, membranous, 1-nerved. Lemma midnerve scaberulous. Lemma apex acute, 1-awned. Median (principal) awn 0.5 mm long overall. Palea with flaps narrower than body or as wide as body, 100% of length of lemma, 2-nerved. Palea keels scaberulous. Apical sterile florets resembling fertile though underdeveloped. Anthers 3, 0.3–0.5 mm long, yellow. Grain with free soft pericarp, ellipsoid or oblong, obtuse.

Continental Distribution:
Australasia.

Australian Distribution:
Western Australia, Northern Territory, South Australia, Queensland, New South Wales, Victoria.

Western Australia: Gardner, Fitzgerald, Hall, Dampier, Mueller, Canning, Keartland, Giles, Helms, Fortescue, Ashburton, Carnarvon, Austin, Eucla, Irwin, Drummond, Avon, Coolgardie. Northern Territory: Darwin & Gulf, Victoria River, Barkly Tableland, Central Australia North, Central Australia South. South Australia: North-western, Lake Eyre, Gairdner-Torrens Basin, Flinders Ranges, Eastern, Eyre Peninsula, Northern Lofty, Southern Lofty, South-eastern. Queensland: Cook, Burke, North Kennedy, South Kennedy, Port Curtis, Leichhardt, Burnett, Darling Downs, Moreton, Gregory North, Gregory South, Mitchell, Warrego, Maranoa. New South Wales: North Coast, Central Coast, Northern Tablelands, North-Western Slopes, Central-Western Slopes, North-Western Plains, South-Western Plains, North Far Western Plains, South Far Western Plains. Victoria: Murray Mallee, Riverina.

Classification. (GPWG 2001):
Chloridoideae: Cynodonteae

Notes
Endemic; distributed through inland areas of all mainland states, and occurring near to the coast and on off-shore islands above 24°S. Recorded growing on many soil types but most often on sand and in seasonally wet areas such as creek-banks and flood-plains; tolerates saline and swampy conditions and appears after flooding. Flowers normally Dec.–June, Oct.

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