Ischaemum rugosum

Ischaemum rugosum Salisb. Icon.
Stirp. Rar.
1 (1791).

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

Type of Basionym or
Protologue Information
: India:
Orissa, ad margines agrorum oryzaceorum, J.G. Koening s.n. (HT: BM).

Key references
(books and floras):
[2002] D.Sharp & B.K.Simon, AusGrass, Grasses of

Habit. Annual.
Culms decumbent, 10–100 cm tall. Mid-culm nodes glabrous or pubescent. Lateral
branches branched. Ligule an eciliate membrane. Leaf-blades 5–30 cm long, 3–15
mm wide.

Inflorescence digitate, a rame, with ramose branches. Rhachis fragile at the

Spikelets sessile, 1 in the cluster. Companion spikelets pedicelled, 1 in the
cluster. Companion spikelets developed or rudimentary, containing empty lemmas
or male, 2–6 mm long. Companion spikelet glumes muticous. 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, 4–6 mm long.

Glumes. Glumes
dissimilar, firmer than fertile lemma. Lower glume ovate, membranous or
coriaceous or indurate, much thinner above, keeled, 2-keeled, winged on keel,
winged narrowly, 15 -nerved. Upper glume lanceolate, membranous or chartaceous,
keeled, 1-keeled, 3 -nerved. Upper glume surface glabrous. Florets.
Basal sterile florets 1, male, with palea. Lemma of lower sterile floret 100 %
of length of spikelet, hyaline or membranous.

Fertile lemma 5 mm
long, without keel. Lemma apex lobed, awned, 1 -awned. Median (principal) awn
from a sinus, 15–20 mm long overall, with a twisted column. Grain 2–2.5 mm

: Africa, Temperate Asia, Tropical Asia, Australasia, Pacific,
North America, and South America.

: Northern Territory, Queensland.

Northern Territory: Darwin &
Gulf. Queensland:
Cook, North Kennedy, South Kennedy.

Notes. Growing
in wet sites in northern N.T. and central and northern coastal Qld. Extends to
most of tropical Asia and introduced to tropical Africa and America.

Infra-specific taxa: var. rugosum, var. segetum .

Pedicelled spikelet
developed                    I. rugosum var. rugosum 

Pedicelled spikelet
much reduced             I. rugosum var. setegum  

Scratchpads developed and conceived by (alphabetical): Ed Baker, Katherine Bouton Alice Heaton Dimitris Koureas, Laurence Livermore, Dave Roberts, Simon Rycroft, Ben Scott, Vince Smith