Dichanthium annulatum*

Dichanthium annulatum* (Forssk.) Stapf. Fl. Trop. Afr. 9: 178 (1917).

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

Basionym and/or Replacement Name:  Andropogon annulatus Forssk., Fl. Aegypt.-Arab.173 (1775).

Type of Basionym or Protologue Information: Egypt: Rashid, banks of Nile River, June 1762, Forsskal 127 (HT: C; IT: LD).

Key references (books and floras): [1878] G.Bentham, Flora Australiensis 7 (531 as Andropogon annulatus), [1952] C.A.Gardner, Flora of Western Australia 1 Gramineae (328), [1969] E.E.Henty, Manual Grasses New Guinea (69), [2002] D.Sharp & B.K.Simon, AusGrass, Grasses of Australia.

Illustrations: [1952] C.A.Gardner, Flora of Western Australia 1 Gramineae (327 & 329, Pl. 95 & 96).

Habit. Perennial. Culms decumbent, 25–100 cm tall. Mid-culm nodes bearded. Lateral branches simple or branched. Ligule an eciliate membrane, 1 mm long. Leaf-blades 3–30 cm long, 2–7 mm wide.

Inflorescence. Inflorescence subdigitate, with ramose branches. Rhachis fragile at the nodes.

Spikelets. Spikelets sessile, 1 in the cluster. Companion spikelets pedicelled, 1 in the cluster. Basal sterile spikelets absent or well-developed, 0–12 in number (lower raceme). Companion spikelets developed, containing empty lemmas or male, 2–6 mm long. 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, oblong, dorsally compressed, 2–6 mm long.

Glumes. Glumes dissimilar, firmer than fertile lemma. Lower glume oblong, cartilaginous, without keels, 7 -nerved. Lower glume surface indumented. Upper glume lanceolate, keeled, 1-keeled, 3 -nerved. Florets. Basal sterile florets 1, barren, without significant palea. Lemma of lower sterile floret hyaline, 0 -nerved.

Fertile lemma 1.6 mm long, without keel, 1 -nerved. Lemma apex entire, awned, 1 -awned. Median (principal) awn apical, 8–25 mm long overall, with a twisted column. Palea absent. Anthers 3. Grain 1.5 mm long.

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

Australian Distribution: Western Australia, Northern Territory, Queensland.

Western Australia: Fortescue. Northern Territory: Darwin & Gulf, Victoria River, Central Australia North, Central Australia South. Queensland: Burke, Cook, Darling Downs, Leichhardt, Mitchell, Moreton, North Kennedy, Port Curtis, South Kennedy, Wide Bay.

Notes. D. annulatum var. papillosum (A. Rich.) de Wet & Harlan from tropical to South Africa has been cultivated.

Malesia and India to the Middle East and West Africa. Naturalised mainly in Queensland coastal areas; sometimes cultivated. Flowers whole year.

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