Rytidosperma dimidiatum (Vickery) H.E.
Connor & E. Edgar. New Zealand J. Bot. 17: 332 (1979).
Classification. (GPWG 2001) : Subfamily Danthonioideae. Tribe
Danthonieae.
Basionym and/or
Replacement Name: Danthonia
dimidiata Vickery, Contr. New South Wales Natl. Herb. 2: 322 (1956).
Type of Basionym or
Protologue Information: HT: Rodway s.n., Australia (HO).
Recent synonyms:
Notodanthonia dimidiata, Danthonia dimidiata.
Key references
(books and floras): [2002] D.Sharp & B.K.Simon, AusGrass, Grasses of
Australia.
Habit.
Perennial. Culms erect or geniculately ascending, stature slender to delicate,
15–40 cm tall, 2–4 -noded. Mid-culm nodes glabrous. Leaf-sheaths glabrous on
surface or hairy. Ligule a fringe of hairs. Leaf-blades involute, 2–12 cm long,
1–1.5 mm wide. Leaf-blade surface glabrous or indumented.
Inflorescence.
Inflorescence solid, a panicle. Panicle linear or lanceolate, 2–6 cm long.
Spikelets.
Spikelets pedicelled. Fertile spikelets many flowered, with at least 2 fertile
florets (4–7), comprising 4–7 fertile floret(s), with diminished florets at the
apex, cuneate, laterally compressed, 5–11 mm long.
Glumes. Glumes
similar, thinner than fertile lemma. Lower glume lanceolate, membranous,
without keels, 7 -nerved. Upper glume lanceolate, 5–11 mm long, membranous,
without keels, 7 -nerved.
Florets.
Fertile lemma 2.5–7 mm long, without keel, 9 -nerved. Lemma surface indumented.
Lemma apex lobed, awned, 1 -awned. Median (principal) awn from a sinus, 7.5–9.5
mm long overall, with a twisted column. Column 4 mm long. Lateral lemma awns
absent. Lodicules present. Anthers 3. Grain 1.5–1.6 mm long.
Continental
Distribution: Australasia.
Australian
Distribution: Victoria, Tasmania.
Victoria:
Gippsland Plain. Tasmania: North East, West Coast, Central Highlands,
Midlands, Ben Lomond, East Coast, South West.
Notes.
R. dimidiatum is closely related to R. fortunae-hibernae and R.
pauciflorum. It differs from the former species by the laxer growth and
larger spikelets; Morris (1992) separates it by a lax ring of lemma hairs
compared to a dense ring directly below the sinus in R. fortunae-hibernae.
It is readily distinguished from R. pauciflorum by the much larger
spikelets and the poorly developed upper row of lemma hairs.
Tasmania
and the southern coast of Victoria, altitude 0–1150 m, various habitats, from
moorland to dry grassland, in exposed places. Flowers Dec.