Whiteochloa cymbiformis

Whiteochloa cymbiformis (Hughes) B.K.Simon. Austrobaileya 2: 23 (1984).

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

Basionym and/or
Replacement Name:
 Panicum cymbiforme
Hughes, Bull. Misc. Inform. Kew 1923(9):
323 (1923).

Type of Basionym or
Protologue Information
: IT: A. Cunningham 341, 1822, Australia: Western Australia (US-1445623 (fragm.)).

Key references
(books and floras):
[1952] C.A.Gardner, Flora of Western Australia 1 Gramineae
(258 as Panicum), [1981] M.Lazarides in J.Jessop (ed)., Flora of
Central Australia
(472 as Panicum cymboforme).

Illustrations:
[1952] C.A.Gardner, Flora of Western
Australia
1 Gramineae (255, Pl.75 as Panicum).

Derivation:
from the Greek kymbe (boat) and forma (appearance).

Habit. Annual
or perennial. Culms 50–200 cm tall. Mid-culm nodes glabrous or pubescent.
Leaf-sheaths glabrous on surface. Ligule a fringed membrane, a ciliolate
membrane, 0.5–1.2 mm long. Leaf-blades 10–40 cm long, 4–15 mm wide.

Inflorescence.
Inflorescence compound, a panicle. Panicle lanceolate or elliptic, 12–70 cm
long, 4–15 cm wide, contracted about primary branches.

Spikelets.
Spikelets pedicelled. 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, laterally
compressed, 2.8–3.9 mm long. Rhachilla internodes elongated between glumes, or
elongated below proximal fertile floret.

Glumes. Glumes
dissimilar, thinner than fertile lemma. Lower glume ovate, membranous, keeled,
1-keeled, 3 -nerved. Lower glume apex mucronate. Upper glume oblong, 2.3–3.2 mm
long, membranous, without keels, 7–9 -nerved. Upper glume surface glabrous. Upper
glume apex muticous. Florets. Basal sterile florets 1, male, with palea.
Lemma of lower sterile floret 100 % of length of spikelet, scarious, 5–7
-nerved, muticous.

Fertile lemma 1.7–2.3
mm long, without keel. Lemma apex muticous. Anthers 3.

Continental
Distribution
: Australasia.

Australian
Distribution
: Western Australia, Northern Territory.

Western Australia: Gardner, Dampier.
Canning, Fortescue, Carnarvon. Northern Territory:
Darwin & Gulf, Victoria River,
Barkly Tableland, Central Australia North.

Notes.
A very interesting feature of W. cymbiformis is the presence of filiform
bristles which terminate some branches. Some specimens completely lack these
structures, however, bristles are usually present. This is the only species
that is variable for this taxonomically very important character. The presence
of a bristle in Whiteochloa is consistent because other genera in the
Paniceae that have a rugose upper floret and C4 subtype NADP are
bristle-bearing. Genera with a rugose upper floret and C4 subtype PCK lack
bristles.

In tropical and subtropical sub-humid woodlands, arid
and semi-arid low woodlands, acacia shrublands, arid tussock grasslands, and
arid hummock grasslands. Flowers mostly Feb.-July.

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