Cymbopogon ambiguus

Cymbopogon ambiguus (Hack.) A. Camus. Rev.
Int. Bot. App. Agric. Trop.
1: 290 (1921).

(GPWG 2001) : Subfamily Panicoideae. Andropogoneae.

Basionym and/or
Replacement Name:
Steud., Syn. Pl. Glumac. 1: 385 (1854).

Type of Basionym or
Protologue Information
: HT: Baudin's Expedition s.n., Australia: Western
Australia: Islands in Sharks
Bay (P (photo, BRI); IT:
BM, S).

Recent synonyms: C. exaltatus auct.

Key references
(books and floras):
[1878] G.Bentham, Flora Australiensis 7 (532 as Andropogon
), [1952] C.A.Gardner, Flora of Western Australia 1 Gramineae
(338 as C. exaltatus), [1981] M.Lazarides in J.Jessop (ed)., Flora of
Central Australia
(489), [2006] J.Jessop, G.R.M.Dashorst, F.M.James, Grasses
of South Australia
(513), [2008] S.W.L.Jacobs, R.D.B.Walley &
D.J.B.Wheeler, Grasses of New South Wales (190).

[2006] J.Jessop, G.R.M.Dashorst, F.M.James, Grasses of South Australia  (514, Fig. 440), [2008] S.W.L.Jacobs,
R.D.B.Whalley & D.J.B.Wheeler, Grasses of New South Wales, 4th edn

Perennial. Culms erect, 30–100 cm tall. Mid-culm internodes glabrous or
pubescent. Leaf-sheaths glabrous on surface. Leaf-sheath auricles absent, or
present. Ligule an eciliate membrane, 1.9–9 mm long, membranous. Leaf-blades
filiform or linear, flat, 15–50 cm long, 1–5 mm wide. Leaf-blade surface
scabrous, glabrous.

Inflorescence compound, composed of rames. Central inflorescence axis 15–40 cm
long. Rhachis fragile at the nodes.

Spikelets sessile, 1 in the cluster. Companion spikelets pedicelled, 1 in the
cluster. Basal sterile spikelets absent. Companion spikelets developed,
comprising 2 subequal glumes without lemmas or male, 3–5 mm long. Companion
spikelet glumes muticous. 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
elliptic or oblong or ovate, dorsally compressed, 4–6.5 mm long.

Glumes. Glumes
dissimilar, firmer than fertile lemma. Lower glume lanceolate or ovate,
chartaceous, keeled, 2-keeled, winged on keel, winged narrowly. Upper glume
lanceolate, keeled, 1-keeled, 3–5 -nerved. Florets. Basal sterile
florets 1, barren, without significant palea. Lemma of lower sterile floret

Fertile lemma without
keel. Lemma apex lobed, awned, 1 -awned. Median (principal) awn from a sinus,
12–20 mm long overall, with a twisted column. Palea absent. Anthers 3. Grain 2
mm long.

: Australasia.

: Western Australia, Northern Territory, South Australia,
Queensland, New South Wales.

Western Australia:
Gardner, Dampier. Canning, Fortescue, Ashburton, Carnarvon, Austin. Irwin,
Drummond, Dale, Menzies, 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, Murray, Southern Lofty. Queensland: Burke, Cook, Gregory North,
Leichhardt, North Kennedy, South Kennedy, Mitchell. New South Wales:
South-Western Plains, North Far Western Plains.

There is considerable variation in the width and colour of the leaf lamina and
the density of the inflorescence within the species. In same habitats (eg.
Standley Chasm, N.T., pers. obs.) it is possible for a number of forms to grow

The most widely
distributed species of Cymbopogon in Australia extending from the arid
interior to tropical coastal areas. There is a single extra Australian record
from the north coast of Timor. Flowers all 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