Ischaemum decumbens

Ischaemum decumbens Benth. Fl.
7: 521 (1878).

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

Type of Basionym or
Protologue Information
: N. Australia, Port Darwin, Schultz 126.

Key references
(books and floras):
[1878] G.Bentham, Flora Australiensis 7 (521),
[2002] D.Sharp & B.K.Simon, AusGrass, Grasses of Australia.

Habit. Annual.
Culms sprawling, 5–40 cm tall. Mid-culm nodes bearded. Lateral branches
branched. Leaf-sheaths glabrous on surface. Ligule a fringed membrane, a
ciliolate membrane, 0.5–1.5 mm long. Leaf-blades linear or lanceolate, 1–5 cm
long, 1–6 mm wide. Leaf-blade surface indumented.

Inflorescence digitate, with ramose branches. Rhachis fragile at the nodes.

Spikelets sessile, 1 in the cluster. Companion spikelets pedicelled, 1 in the
cluster. Companion spikelets developed, comprising 2 subequal glumes without
lemmas, 2–6 mm long. Companion spikelet glumes awned. 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, oblong or ovate, dorsally compressed, 5–10 mm long.

Glumes dissimilar, firmer than fertile lemma, shiny. Lower glume ovate,
coriaceous, without keels or keeled, 2-keeled, wingless, 11 -nerved. Lower
glume surface glabrous. Lower glume apex awned. Upper glume lanceolate, 4 mm
long, membranous or coriaceous, keeled, 1-keeled, winged on keel, 5 -nerved.
Upper glume surface glabrous or indumented. Upper glume apex awned. Florets.
Basal sterile florets 1, male, with palea. Lemma of lower sterile floret
hyaline or membranous, 3 -nerved.

Fertile lemma 3 mm
long, without keel. Lemma apex lobed, awned, 1 -awned. Median (principal) awn
from a sinus, 12–14 mm long overall, with a twisted column. Palea present.
Anthers 3. Grain 1 mm long.

: Australasia.

: Northern Territory, Queensland.

Northern Territory: Darwin &
Gulf. Queensland:

Notes. Grows in
damp to wet areas of sandy soil in Melaleuca savanna woodland in
northern N.T. and Qld. Flowers Apr.--Oct.

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