Danthonia* Lam. & DC., Fl. Franc. 3rd edn, 3: 32 (1805) nom. conserv.
Derivation:. Named for Etienne Danthoine, French botanist, of Marseille.
Syn: Syn. Sieglingia Bernh.
Key references (keys and floras):. G.Bentham, Flora Australiensis 7: 590–596 (1878), incl. Austrodanthonia, Notodanthonia, Rytidosperma; J.C.Tothill and J.B.Hacker, Grasses of Southern Queenland 180–182 (1983) incl. Austrodanthonia, Notodanthonia, Rytidosperma; B.K.Simon, Key to Australian Grasses 90–94 (1993), incl. Austrodanthonia, Notodanthonia, Rytidosperma; S.W.L.Jacobs and S.M.Hastings, Flora of New South Wales 4: 548–557 (1993), incl. Austrodanthonia, Notodanthonia, Rytidosperma; N.G.Walsh, Flora of Victoria 2: 527–543(1994), incl. Austrodanthonia, Notodanthonia, Rytidosperma and 2: 524 (1994) as Sieglingia; D.I.Morris, Student's Flora of Tasmania 4B: 304–317 (1994) incl. Austrodanthonia, Notodanthonia, Rytidosperma; E.Edgar and H.E.Connor, Flora of New Zealand 5: 21–23(2000) as Sieglingia; D.Sharp and B.K.Simon, AusGrass (2002); K.Mallet (ed.), Flora of Australia 44B: Poaceae 3: 29 (2005).
W.D.Clayton & S.A.Renvoize, Genera Graminum (1986), genus (295).
Naturalised. 20 species, from temperate regions. 1 species in Australia, Vic and Tas. Also New Zealand.
Habit. Perennial, tufted. Leaf blades narrow. Ligule a fringe of hairs.
Inflorescence. Inflorescence paniculate (sometimes reduced almost to a raceme), a spike-like panicle, open.
Spikelets. Spikelets laterally compressed, more than 2 flowered, with 1 fertile floret, awned, solitary, pedicelled; with naked rachilla extension. Fertile spikelets disarticulating above glumes.
Glumes. Glumes more or less equal, about equal to spikelet to exceeding florets, long relative to adjacent lemmas, pointed, awnless, similar (papery). Lower glume 3–7 nerved. Upper glume 3–7 nerved.
Florets. Fertile florets 3–15. Lemmas similar in texture to glumes to decidedly firmer than glumes, not becoming indurated, incised, deeply cleft or not deeply cleft, muticous or mucronate, without a germination flap, 7–15 nerved (?), nearly always hairy, not keeled. Awns 1 or 3, the median different in form from laterals (when laterals present), from a sinus, geniculate, much shorter than body of lemma to much longer than body of lemma. Lateral awns when present shorter than median to exceeding median (straight, terminating the lobes). Lemma hairs in tufts or not in tufts, in transverse rows or not in transverse rows. Palea relatively long to conspicuous and relatively short, entire to apically notched, 2 nerved. Palea keels wingless. Callus short to long, pointed. Lodicules 2. Stamens 3. Grain small, longitudinally grooved. Hilum usually long-linear. Embryo large.
Kranz Anatomy. C3.
2n = 18, 36, and 48, 2 and 4 ploid.
Habitat. Mesophytic to xerophytic. Grasslands and open woodlands, often in hilly regions. Species of open habitats.
Notes. Danthonia is commonly treated in a wide sense to include Chionochloa, Rytidosperma and a number of lesser satellite genera, since they are all closely related and difficult to separate. By using a combination of lemma indumentum, lodicule hairs and hilum length, these genera can be tolerably well defined, and their recognition has the advantage of throwing some light on the taxonomy of an otherwise unwieldy agglomeration of species. On the other hand the characters employed are of marginal significance at generic level and even then boundaries are somewhat blurred by awkward intermediates, implying that splitting has proceeded too far. In either case generic concepts in this group are highly controversial (Clayton & Renvoize, 1986). Australian botanists follow the concepts of Linder and Verboom (1996), who analysed the danthonioid group using cladistic methods and recognised the genera Austrodanthonia, Rytidosperma, Notodanthonia, Chionochloa etc. based on small but distinct morphological characters. The only Australian representative of Danthonia recognised is Danthonia decumbens, placed by some authorities in Sieglingia. The recent Flora of New Zealand account (Edgar and Connor 2000) has not followed recognising the segregates of Linder, but does accept Sieglingia (B.K.Simon).
Types Species. D. spicata (L.) Roem.& Schult.
Biogeographic Element. Clifford & Simon 1981, Simon & Jacobs 1990: Naturalised.