Cynodon radiatus* Roth ex Roem. & Schult. Syst. Veg. 2: 411 (1817).
Classification. (GPWG 2001) : Subfamily Chloridoideae. Cynodonteae.
Type of Basionym or
Protologue Information: India:
1814, B. Heyne s.n. (HT: L).
Recent synonyms:
C. arcuatus.
Key references
(books and floras): [1980] M.Lazarides, Tropical Grasses S.E.Asia
(as C. dactylon ssp. arcuatus), [2002] D.Sharp & B.K.Simon, AusGrass,
Grasses of Australia.
Illustrations:
[2005] K.Mallet (ed.), Flora of Australia 44B: Poaceae 3
(Fig. 53I-L).
Habit. Annual.
Rhizomes absent. Stolons present. Culms erect or geniculately ascending,
stature slender to delicate, 15–80 cm tall, 1–2 mm diam., wiry. Ligule a
fringed membrane, a ciliolate membrane, 0.3–0.5 mm long. Leaf-blades linear or
lanceolate, 4–17 cm long, 3–6(–10) mm wide. Leaf-blade surface scaberulous,
glabrous.
Inflorescence.
Inflorescence digitate, with spicate branches. Racemes drooping, flexuous.
Spikelets.
Spikelets sessile. Fertile spikelets 1-flowered, comprising 1 fertile
floret(s), without rachilla extension, ovate, laterally compressed, 1.6–2.2 mm
long.
Glumes. Glumes
similar, thinner than fertile lemma. Lower glume lanceolate, membranous,
keeled, 1-keeled, 1 -nerved. Upper glume lanceolate, 1–1.4(–1.9) mm long,
membranous, keeled, 1-keeled, 1 -nerved.
Florets.
Fertile lemma 1.6–2(–2.2) mm long, keeled, wingless, 3 -nerved. Lemma surface
indumented. Palea 2 -nerved. Anthers 3.
Continental
Distribution: Africa, or Temperate Asia, or Tropical Asia, or Australasia.
Australian
Distribution: Western Australia, Northern Territory, Queensland, Cocos Keeling Is, Ashmore Reef, Coral Sea Is.
Northern Territory: Darwin &
Gulf. Queensland:
North Kennedy. Western Australia: Gardner
Notes.
Vigorously spreading colonizer of disturbed sites.
Cynodon radiatus can be distinguished
from C. dactylon by its coarser habit, broader blades, and relatively
slender inflorescence of longer, flaccid, pallid spikes. In indumentum the
auricles and orifice are glabrous or sparsely bearded (always bearded in C.
dactylon), the lateral nerves of the lemma are shortly hairy (not
glabrous), and the keels of the palea are smooth (not scabrous). Furthermore,
the ligule is somewhat longer, the anthers are distinctly smaller, and the
grain is unequally trigonous and laterally compressed (turgid or scarcely
compressed in C. dactylon). Rhizomes are absent (present in C.
dactylon).
.
Occurs
within a 200 km radius of Darwin; Madagasgar, SE
Asia, India, Burma, Malesia, New Guinea and North
America. Most frequently found in woodlands of Eucalyptus,
Callitris or Melaleuca, on disturbed sites, often in or near creeks,
sometimes at rainforest margins, in a variety of soil types from sand to dark
brown loam. Reported to spread profusely by stolons up to 1.5 m in length.
