Setaria dielsii Herrm. Beitr.
Biol. Pflanzen. 10: 52 (1910).
Classification. (GPWG 2001) : Subfamily
Panicoideae. Paniceae.
Type of Basionym or
Protologue Information: ST: Koch 170, May 1898, Australia: South Australia:
am Mt. Lindhurst (B, US-2435844 (fragm.)). ST: Diels
3664, Australia:
West-Australien, Gascogne bei Carmarvon (US). ST: A. Cunningham s.n., Australia:
Nordwest-Austrlien, ohne Standortsangabe (B).
Key references
(books and floras): [1952] C.A.Gardner, Flora of Western Australia 1
Gramineae (267), [1981] M.Lazarides in J.Jessop (ed)., Flora of
Central Australia (481), [2002] D.Sharp & B.K.Simon, AusGrass,
Grasses of Australia, [2006] J.Jessop, G.R.M.Dashorst, F.M.James, Grasses
of South Australia (480).
Illustrations:
[1952] C.A.Gardner, Flora of Western Australia
1 Gramineae (269, Pl. 77), [2006] J.Jessop, G.R.M.Dashorst, F.M.James, Grasses
of South Australia
(480, Fig. 412).
Habit. Annual.
Rhizomes absent. Stolons absent or present. Culms erect or geniculately
ascending or decumbent, 40–80 cm tall, 3–6 -noded. Mid-culm nodes glabrous.
Leaf-sheaths glabrous on surface. Ligule a fringe of hairs, 0.5–1.3 mm long.
Leaf-blades flat, 5–28 cm long, 3.5–11 mm wide. Leaf-blade surface scabrous,
glabrous.
Inflorescence.
Inflorescence compound, a panicle. Panicle lanceolate, 2.5–17 cm long,
contracted about primary branches.
Spikelets.
Spikelets sessile. 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, 2.1–2.8 mm long.
Glumes. Glumes
thinner than fertile lemma. Lower glume ovate, membranous, without keels, 3
-nerved. Upper glume elliptic, 2.1–2.8 mm long, membranous, without keels, 7–9
-nerved. Florets. Basal sterile florets 1, barren, without significant
palea. Lemma of lower sterile floret 100 % of length of spikelet, membranous,
5–7 -nerved.
Fertile lemma 2.1–2.8
mm long, without keel. Lemma apex mucronate.
Continental
Distribution: Australasia.
Australian
Distribution: Western Australia, Northern Territory, South Australia,
Queensland.
Western Australia: Dampier. Warren. Northern
Territory: Central Australia North, Central
Australia South. South Australia:
North-western, Lake Eyre, Gairdner-Torrens
Basin, Flinders Ranges,
Eastern. Queensland:
North Kennedy, South Kennedy, Leichhardt.
Notes.
The primary branches of the inflorescence are well developed and a single
bristle subtends the terminal and basal spikelets. This bristle to spikelet
relationship is identical to that of the genus Paspalidium and
intermediate between the very compacted or reduced form represented by S.
geniculata and the open form represented by S. palmifolia.
Setaria dielsii seems to be very
similar to some North American species of Setaria (e.g. S.
grisebachii) and more critical study of Australian species is needed.
In Brigalow forests,
acacia shrublands, and arid hummock grasslands. Flowers sporadically throughout
the year.
