Digitaria didactyla*

Digitaria didactyla* Willd. Enum. Hort. Berol. 91 (1809).

Classification. (GPWG 2001) : Subfamily Panicoideae. Paniceae.

Type of Basionym or Protologue Information: HT: Bory de St. Vincent s.n., Mauritius (B-W-1646; IT: BM).

Key references (books and floras): [1969] E.E.Henty, Manual Grasses New Guinea (76), [2002] D.Sharp & B.K.Simon, AusGrass, Grasses of Australia, [2008] S.W.L.Jacobs, R.D.B.Walley & D.J.B.Wheeler, Grasses of New South Wales (216).

Illustrations: [2008] S.W.L.Jacobs, R.D.B.Whalley & D.J.B.Wheeler, Grasses of New South Wales, 4th edn (216).

Habit. Perennial. Rhizomes absent or present, elongated. Culms decumbent or prostrate, 10–60 cm tall, 1–5 -noded. Mid-culm internodes glabrous. Mid-culm nodes glabrous. Leaf-sheaths smooth or scaberulous, glabrous on surface or hairy. Leaf-sheath auricles absent. Ligule an eciliate membrane, 0.8 mm long. Leaf-blades flat or conduplicate, 1.9–6(–10) cm long, 1–6 mm wide. Leaf-blade surface smooth, glabrous or indumented.

Inflorescence. Inflorescence digitate, with racemose branches. Racemes 2–3(–4), 3–10 cm long.

Spikelets. Spikelets pedicelled, 2 in the cluster. Fertile spikelets 2-flowered, the lower floret barren (rarely male), the upper fertile, comprising 1 basal sterile florets, comprising 1 fertile floret(s), without rachilla extension, lanceolate or oblong, dorsally compressed, (2–)2.2–2.7 mm long. Rhachilla internodes brief up to lowest fertile floret.

Glumes. Glumes dissimilar, thinner than fertile lemma. Lower glume ovate, membranous, without keels, 0 -nerved. Upper glume ovate, 1.3–1.6 mm long, membranous, without keels, 3 -nerved. Upper glume surface indumented. Florets. Basal sterile florets 1, barren, without significant palea. Lemma of lower sterile floret 100 % of length of spikelet, membranous, 5–7 -nerved.

Fertile lemma 2–2.7 mm long, without keel. Lemma apex muticous or mucronate. Lodicules present.

Continental Distribution: Africa, Tropical Asia, Australasia, Pacific, and South America.

Australian Distribution: Western Australia, Queensland, New South Wales.

Western Australia: Drummond, Dale, Menzies, Warren. Queensland: Moreton, North Kennedy, Port Curtis, Wide Bay, Cook, South Kennedy. New South Wales: North Coast, Central Coast, Central-Western Slopes.

Notes. In tropical and subtropical wet sclerophyll forests, Brigalow forests, and tropical and subtropical sub-humid woodlands. Introduced in the early 1900's as a lawn grass, now occurs sporadically in disturbed sites and is most competitive in moist sandy soils. Flowers mostly Jan.-May.

AVH 2011


Scratchpads developed and conceived by (alphabetical): Ed Baker, Katherine Bouton Alice Heaton Dimitris Koureas, Laurence Livermore, Dave Roberts, Simon Rycroft, Ben Scott, Vince Smith