Pseudopogonatherum irritans

Pseudopogonatherum irritans (R.Br.) A.Camus. Ann.
Soc. Linn. Lyon
. 68: 205 (1921).

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

Basionym and/or
Replacement Name:
 Saccharum
irritans
R. Br., Prodr. 1: 203 (1810).

Type of Basionym or
Protologue Information
: (T.) Littora Novae Hollandiae intra tropicum,.

Key references
(books and floras):
[1810]. R.Brown, Prodromus (203 as Saccharum
irritans
), [1878] G.Bentham, Flora Australiensis 7 (525 as Pollinia
irritans
), [2002] D.Sharp & B.K.Simon, AusGrass, Grasses of Australia.

Habit. Annual.
Culms erect, 50–150 cm tall, 6–8 -noded. Mid-culm nodes glabrous. Lateral
branches simple. Leaf-sheaths glabrous on surface. Ligule a fringed membrane, a
ciliolate membrane, 0.3–0.5 mm long. Leaf-blades filiform, involute, 15–50 cm
long, 1–3 mm wide. Leaf-blade surface indumented.

Inflorescence.
Inflorescence subdigitate, with racemose branches. Racemes numerous, 3–20,
erect or ascending, 3–6 cm long. Central inflorescence axis 1–3 cm long.
Rhachis tough or fragile at the nodes.

Spikelets.
Spikelets sessile and pedicelled or pedicelled (when tough), 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, elliptic, dorsally compressed, 2.5–5 mm long.

Glumes. Glumes
dissimilar, firmer than fertile lemma. Lower glume linear or lanceolate or
oblong, chartaceous, without keels or keeled, 2-keeled, 2 -nerved. Lower glume
surface indumented. Upper glume oblong, keeled, 1-keeled, 1–3 -nerved. Upper
glume surface indumented. Upper glume apex awned. Florets. Basal sterile
florets 1.

Fertile lemma 1.5–2.5
mm long, without keel. Lemma apex lobed, awned, 1 -awned. Median (principal)
awn from a sinus, 30–50 mm long overall, with a twisted column. Palea absent.
Anthers 3. Grain 2 mm long.

Continental
Distribution
: Tropical Asia and Australasia.

Australian
Distribution
: Western Australia, Northern Territory, Queensland.

Western
Australia
: Gardner.
Northern Territory:
Darwin & Gulf. Queensland:
Cook, North Kennedy, South Kennedy, Port Curtis.

Notes. Occurs
sporadically in savanna and heath in northern Australia
and extends to New Guinea,
Malesia and Burma.
Flowers Dec.--July.

 

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