Rottboellia cochinchinensis*

Rottboellia cochinchinensis* (Lour.)
Clayton. Kew Bull. 35: 817 (1981).

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

Basionym and/or
Replacement Name:
Lour., Fl. Cochinch. 51 (1790).

Type of Basionym or
Protologue Information
: Vietnam.

Recent synonyms:
R. exaltata.

Key references
(books and floras):
[1810]. R.Brown, Prodromus (206 as Rottboellia
), [1878] G.Bentham, Flora Australiensis 7 (513 as Rottboellia
), [2002] D.Sharp & B.K.Simon, AusGrass, Grasses of
, [2008] S.W.L.Jacobs, R.D.B.Walley & D.J.B.Wheeler, Grasses
of New South Wales

[2008] S.W.L.Jacobs, R.D.B.Whalley & D.J.B.Wheeler, Grasses of New South
, 4th edn (361).

Habit. Annual.
Culms erect, 30–300 cm tall. Mid-culm nodes glabrous. Lateral branches
branched. Leaves cauline. Leaf-sheaths hairy. Ligule a fringed membrane, a
ciliolate membrane, 1–1.5 mm long, truncate. Leaf-blades 15–50 cm long, 5–30 mm
wide. Leaf-blade surface scaberulous.

Inflorescence solid, a rame. Rhachis fragile at the nodes.

Spikelets sessile, 1 in the cluster. Companion spikelets pedicelled, 1 in the
cluster. Companion spikelets developed, containing empty lemmas, 3–5 mm long.
Companion spikelet glumes muticous. Apical sterile spikelets barren. 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, ovate, dorsally compressed, 3.5–6 mm long.

Glumes dissimilar, firmer than fertile lemma. Lower glume oblong or ovate,
indurate, keeled, 2-keeled, winged on keel, 9–13 -nerved. Lower glume surface
glabrous. Upper glume oblong or ovate, chartaceous or coriaceous, keeled,
1-keeled, winged on keel, 11–15 -nerved. Upper glume surface glabrous. Florets.
Basal sterile florets 1, male, with palea. Lemma of lower sterile floret 100 %
of length of spikelet, hyaline, 5 -nerved.

Fertile lemma 2.5–4.5
mm long, keeled, 1 -nerved. Palea 0 -nerved, without keels. Lodicules present.
Anthers 3. Grain 3.5 mm long.

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

: Northern Territory, Queensland, New South Wales, Christmas

Northern Territory:
Darwin & Gulf. Queensland: Cook, Leichhardt, Moreton, North Kennedy,
Mitchell. New South Wales: Central Coast.

Notes. A
pantropical species growing in wet sites, commonly as a weed. Found in
Australia in tropical coastal Qld and N.T.; Lord Howe Is. One record from
N.S.W. Flowers Jan.--Sept.


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