Chionachne Pl. Jav. Rar. 15, 18

From Greek chion (snow) and achne (glume) in allusion to the pale
coloured glumes of some species.

Key references
(keys and floras):
. G.Bentham, Flora Australiensis 7: 515–516
(1878); C.A.Gardner, Flora of Western Australia 1 Gramineae
354–358 (1952); E.E.Henty, Manual Grasses New Guinea 51 (1969) as
Polytoca; M.Lazarides, Tropical Grasses S.E. Asia 94 (1980);
J.C.Tothill and J.B.Hacker, Grasses of Southern Queensland 152–153
(1983); B.K.Simon, Flora of the Kimberley Region 1136, 1138 (1992);
B.K.Simon, Key to Australian Grasses 84 (1993); D.Sharp and B.K.Simon, AusGrass

W.D.Clayton &
S.A.Renvoize, Genera Graminum (1986), genus (647).

Native. 7 species,
from Indomalayan region and eastern Australia. 2 species in Australia, WA, NT,
and Qld. Also New Guinea and Malesia.

Habit. Annual
(rarely) or perennial (reed-like), rhizomatous or tufted. Culms woody and
persistent, or herbaceous. Leaf blades broad. Ligule an unfringed membrane to a
fringed membrane (ciliate). Plants monoecious with all fertile spikelets
unisexual, male and female-fertile spikelets segregated, in different parts of
same inflorescence branch (female spikelets few, near the bases of the spikes,
the male spikelets distal).

Inflorescence leafy, paniculate (of inflorescence branches that are spicate and
female at the base and racemose and male at the apex), a spatheathe panicle,
spatheate, a compound pseudo-inflorescence. Spikelet-bearing axes racemes to
spikelike, solitary or paired or clustered, disarticulating at joints.

Spikelets all partially embedded in rachis, dorsally compressed, 2 flowered,
with 1 fertile floret, solitary (female spikelets) or paired (male spikelets),
sessile and pedicelled (in male spikelets), in pedicelled/sessile combinations.
Fertile spikelets falling with glumes.

Glumes. Glumes
unequal, (the longer) long relative to adjacent lemmas, awnless, dissimilar
(lower bigger, tough, rounded, with wings clasping the spikelet, the upper
smaller, not tough, flat). Lower glume 7–20 nerved. Upper glume 7–9 nerved.

Florets. Lower
incomplete floret(s) male. Lemmas awnless, 3 nerved, not becoming indurated.
Fertile florets female 1. Lemmas less firm than glumes (membranous), not
becoming indurated, muticous, 1–5 nerved, glabrous. Palea relatively long, 2
nerved. Grain small, compressed dorsiventrally. Hilum short. Embryo large.
Pedicels free of rachis.

Kranz Anatomy.

2n = 20,
2 ploid.

Habitat. Helophytic
to mesophytic. Forest margins, streamsides.

Panicoideae; Andropogoneae.

Notes. Chionachne,
together with Sclerachne, Polytoca and Trilobachne,
belongs to a close-knit subtribe (Chionachninae), the genera separated by
relatively slight differences. The sessile spikelet callus clearly indicates a
derivation from Rottboelliinae. The slender composite internode-pedicel is
distinctive (Clayton & Renvoize, 1986).

Types Species. C.
(Roxb.) Benth.

. Clifford & Simon 1981, Simon & Jacobs 1990: Indo-Malayan.

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