Urochloa reptans (L.) Stapf. Hooker's
Icon. Pl. t. 3363: 3 (1938.
Classification. (GPWG 2001) : Subfamily
Panicoideae. Paniceae.
Basionym and/or
Replacement Name: Panicum reptans
L., Syst. Nat. (ed. 10) 2: 870 (1759).
Type of Basionym or
Protologue Information: Jamaica:,
P. Browne s.n. (LT: LINN-80.52).
Recent synonyms:
Brachiaria reptans.
Key references
(books and floras): [1878] G.Bentham, Flora Australiensis 7 (476 as Panicum
prostratum), [1952] C.A.Gardner, Flora of Western
Australia 1 Gramineae (236 as Brachiaria),
[2002] D.Sharp & B.K.Simon, AusGrass, Grasses of Australia
(as Brachiaria).
Habit. Annual.
Rhizomes absent. Stolons present. Culms decumbent, 10–60 cm tall. Mid-culm
internodes glabrous. Mid-culm nodes pubescent. Ligule a fringe of hairs.
Leaf-blades lanceolate, 1.5–8 cm long, 3–15 mm wide. Leaf-blade surface
glabrous or indumented.
Inflorescence.
Inflorescence compound, a panicle of racemes. Racemes 5–15, 1–4 cm long, 1–2 mm
wide. Central inflorescence axis 1–8 cm long.
Spikelets.
Spikelets sessile and pedicelled. 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
or oblong, dorsally compressed, 1.5–2.2 mm long. Rhachilla internodes brief up
to lowest fertile floret.
Glumes. Glumes
dissimilar, thinner than fertile lemma. Lower glume orbicular, hyaline, without
keels, 0–1 -nerved. Upper glume ovate, 1.7–2.2 mm long, membranous, without
keels, 7 -nerved. Upper glume surface glabrous. Upper glume apex muticous. Florets.
Basal sterile florets 1, male or barren, with palea. Lemma of lower sterile
floret 100 % of length of spikelet, membranous, 5 -nerved.
Fertile lemma 1–2 mm
long, without keel. Lemma apex mucronate. Palea without keels.
Continental Distribution:
Africa, Temperate Asia, Tropical Asia, Australasia, Pacific, North America, and
South America.
Australian
Distribution: Western Australia, Northern Territory, Queensland, Christmas Is.
Western Australia: Gardner,
Fitzgerald. Giles. Northern Territory: Darwin &
Gulf, Victoria
River. Queensland:
Burke, Leichhardt, Moreton, North Kennedy, Port Curtis, South Kennedy.
Notes.
Some specimens illustrate the problem at generic level of spikelet orientation.
At the base of the primary branch the spikelets will frequently occur singly
and abaxial to the rachis (here the rachis is the primary branch). The solitary
spikelet represents the upper spikelet of a pair as a vestigial lower spikelet
can frequently be observed. The spikelets soon become paired and the lower
spikelet is adaxial to the rachis (here the rachis is the secondary branch).
Towards the apex of the primary branch the spikelets frequently become solitary
and adaxial. This solitary spikelet represents the lower spikelet of the pair.
Here, it is the upper spikelet which is lost. In traditional Urochloa
species it is the lower spikelet which is lost or vestigial towards the apex.
Native to Asia but now occurs throughout the tropics. In tropical
and subtropical rain forests, Brigalow forests, tropical and subtropical
sub-humid woodlands, semi-arid shrub woodlands, arid and semi-arid low
woodlands, coastal grasslands, and tropical sub-humid grasslands. Flowers
Jan.-Aug.
