Common name
Queensland Bluegrass
Slender Bluegrass
Tassel Bluegrass
Silky Bluegrass

Derivation
Dichanthium Willemet, Ann. Bot. (Usteri) 18: 11 (1796). From the Greek dicha (in two) and anthos (flowers), alluding to the two kinds of spikelet pairs in the raceme.

sericeum- from the Latin sericus (silken) and -ea (indicating resemblance). Densely invested in part or totally with long hairs.

Published in
Bull. Mus. Hist. Nat. (Paris) 27: 549 (1921).

Common synonyms
Dichanthium humilius J.M.Black
Dichanthium affine (R.Br.) A.Camus
Dichanthium superciliatum (Hack.) A.Camus
Dichanthium tenuiculum (Steud.) S.T.Blake

Habit
Annual or perennial, tufted. Culms erect, of moderate stature, 10–120 cm tall, 4-noded. Mid-culm internodes channelled. Mid-culm nodes bearded. Lateral branches simple or sparsely branched. Leaf-sheaths glabrous on surface or pilose, with tubercle-based hairs. Ligule an eciliate membrane, 0.5–1 mm long. Leaf-blades 8–15 cm long, 2–4 mm wide, mid-green or glaucous. Leaf-blade midrib evident. Leaf-blade surface glabrous or pilose, with tubercle-based hairs. Leaf-blade apex attenuate.

Inflorescence
Inflorescence with ramose branches. Rames single or paired or digitate, 1.5–7 cm long. Rhachis fragile at the nodes, subterete, ciliate on margins. Rhachis hairs lengthening towards internode tip, 1–1.5 mm long. Rame internodes linear, 1.5–2 mm long.

Spikelets
Spikelets in pairs, one sessile and fertile and the other (companion) spikelet pedicelled. Pedicels linear, 2 mm long, without a translucent median line, ciliate, hairy all along but hairs longer above, with 1–1.5 mm long hairs. Basal sterile spikelets well-developed, 2–6 in number. Basal sterile spikelets barren, smaller than fertile. Basal sterile spikelet lemmas awnless. Companion spikelets developed, sterile, containing empty lemmas, obovate, 3–5 mm long, shorter than fertile, separately deciduous. Companion spikelet glumes 8-nerved, ciliate on margins. Companion spikelet lemmas enclosed by glumes, muticous. Fertile spikelets 2-flowered, comprising 1 fertile floret, lower floret sterile, upper fertile, without rhachilla extension, oblong, dorsally compressed, 4–4.5 mm long, 1.25 mm wide, falling entire, deciduous with accessory branch structures. Spikelet callus pubescent, base obtuse, attached transversely.

Glumes
Glumes dissimilar, firmer than fertile lemma. Lower glume oblong, equalling spikelet, membranous or chartaceous or indurate, much thinner above, keel-less except near apex, 5–8-nerved. Lower glume surface convex or flat or concave. Lower glume surface tuberculate (along fringe), pubescent or pilose, hairy below, with a transverse fringe of hair. Lower glume margins ciliate. Lower glume hairs 5–6 mm long. Lower glume apex truncate or obtuse. Upper glume lanceolate, 1-keeled, 3-nerved. Upper glume surface glabrous. Upper glume apex erose, truncate.

Florets
Basal sterile floret 1, without significant palea. Lemma of lower sterile floret lanceolate or ovate, 1.5–2.5 mm long, hyaline, glabrous, obtuse or acute. Fertile lemma linear, hyaline, 1-nerved. Lemma apex entire,1-awned. Median (principal) awn apical, geniculate, 25–32 mm long overall, with a twisted column. Column glabrous. Palea absent or minute. Anthers 3, 1 mm long. Grain with adherent pericarp, obovoid, 1–2 mm long.

Continental Distribution:
Tropical Asia, Australasia, Pacific, North America.

Australian Distribution:
Western Australia, Northern Territory, South Australia, Queensland, New South Wales, Victoria, Tasmania.

Western Australia: Gardner, Fitzgerald, Hall, Dampier, Mueller, Canning, Giles, Fortescue, Ashburton, Carnarvon, Austin, Coolgardie. Northern Territory: Darwin & Gulf, Victoria River, Barkly Tableland, Central Australia North, Central Australia South. South Australia: North-western, Lake Eyre, Gairdner-Torrens Basin, Flinders Ranges, Eastern, Northern Lofty, Southern Lofty, South-eastern. Queensland: Cook, Burke, North Kennedy, South Kennedy, Port Curtis, Leichhardt, Burnett, Wide Bay, Darling Downs, Moreton, Gregory North, Gregory South, Mitchell, Warrego, Maranoa. New South Wales: North Coast, Central Coast, Northern Tablelands, Central Tablelands, Southern Tablelands, North-Western Slopes, Central-Western Slopes, South-Western Slopes, North-Western Plains, South-Western Plains, North Far Western Plains, South Far Western Plains. Victoria: Wimmera, Riverina, Midlands, Victorian Volcanic Plain, East Gippsland. Tasmania: East Coast.

Classification. (GPWG 2001):
Panicoideae: Andropogoneae

Notes
A valuable pasture species.
There are 3 subspecies:

Dichanthium sericeum subsp. polystachyum (Benth.) B.K.Simon
Native. Found mainly in open wet grassland on wet soil, in tropical W.A., N.T. and Qld. Extends to southern New Guinea. Flowers Jan.–Aug., Oct.–Nov.

Dichanthium sericeum subsp. sericeum
Native. Found in all states, but mainly in the eastern States, in open grassland on clay soils. Extends to New Guinea and naturalised in New Caledonia, the Philippines and SE Asia. Flowers Nov.–Sept.

Dichanthium sericeum subsp. humilius (J.M.Black) B.K.Simon
Native. Found in all mainland states except Vic., north of 29º S in open grassland and open Eucalyptus woodland on clay to sandy soils. Naturalised in Texas and India. Flowers whole year.