Echinochloa

Echinochloa P.Beauv., Ess. Agrostogr. 53 (1812).

Derivation:. From Greek echinos (hedgehog) and chloe (grass), alluding to the bristly spines or hairs on the spikelets.

Taxonomic revisions, nomenclatural references:. P.Michael, Weed Control in Rice 291–306 (1983).

Key references (keys and floras):. C.A.Gardner, Flora of Western Australia 1 Gramineae 253–254 (1952); E.E.Henty, Manual Grasses New Guinea 81, 84 (1969); J.W.Vickery, Flora of New South Wales, Gramineae 19: 189–211 (1975); M.Lazarides, Tropical Grasses S.E. Asia 118–120 (1980); M.Lazarides, Flora of Central Australia 476–477 (1981); J.C.Tothill and J.B.Hacker, Grasses of Southern Queensland 204–206 (1983); J.P.Jessop, Flora of South Australia 4: 1965–1966 (1986); R.D.Webster, Australian Paniceae 71–86 (1987); T.D.Macfarlane, Flora of the Kimberley Region 1152–1155 (1992); B.K.Simon, Key to Australian Grasses 104–106 (1993); S.W.L.Jacobs and S.M.Hastings, Flora of New South Wales 4: 472–477 (1993); N.G.Walsh, Flora Victoria 2: 591–594 (1994); D.I.Morris, Student's Flora of Tasmania 4B: 335–338 (1994); E.Edgar and H.E.Connor, Flora of New Zealand 5: 545–550 (2000); D.Sharp and B.K.Simon, AusGrass (2002); J.P.Jessop, Grasses of South Australia 444–450 (2006);S.W.L.Jacobs, R.D.B.Whalley & D.J.B.Wheeler, Grasses of New South Wales, 4th Ed, 224–229 (2008).

W.D.Clayton & S.A.Renvoize, Genera Graminum (1986), genus (476).

Native and naturalised. 30–40 species, from warm regions. 19 species in Australia, WA, NT, SA, Qld, NSW, Vic, and Tas. Also New Guinea, Malesia and New Zealand.

Habit. Annual or perennial, tufted to decumbent (or floating). Leaf blades broad or narrow. Ligule when present, a fringe of hairs.

Inflorescence. Inflorescence of spicate main branches (the spikelets often hispid), a racemose panicle with spikelets all similar.

Spikelets. Spikelets dorsally compressed, 2 flowered, with 1 fertile floret, awned, paired, or clustered in little secondary racemelets, grouped along one side of branch, shortly pedicelled or subsessile. Fertile spikelets with lower incomplete floret(s), elliptic or lanceolate or ovate, adaxial (with lower glume against rachis) (probably best interpreted as adaxial relative to the reduced, spikelet-bearing branch), falling with glumes.

Glumes. Glumes unequal, (the upper) shorter than adjacent lemmas to long relative to adjacent lemmas, pointed, awned or awnless, with keel conspicuously winged or without a median keel-wing, dissimilar (the lower glume usually much shorter, ovate, often mucronate, the upper glume strongly concave, acute, cuspidate or awned). Lower glume 0–3 nerved. Upper glume 5 nerved or 7 nerved.

Florets. Lower incomplete floret(s) male (rarely), or sterile. Lemmas similar to the upper glume but flattened on the back, often with a large cusp or awned, awned or awnless, 5 nerved, less firm than fertile lemmas to similar in texture to fertile lemmas, not becoming indurated. Fertile florets 1. Lemmas usually blunt-apiculate, with a laterally compressed, incurved beak, decidedly firmer than glumes, smooth, becoming indurated to not becoming indurated (subleathery to crustaceous), yellow in fruit, entire at apex, muticous (obtuse to apiculate), with a clear germination flap, 5 nerved, glabrous (shiny), having margins tucked into palea. Palea relatively long, entire, textured like lemma, indurated or not indurated, 2 nerved. Stamens 3. Grain small, compressed dorsiventrally. Hilum short. Embryo large.

Kranz Anatomy. C4, biochemical type NADP-ME (3 species).

2n = 27, 36, 42, 48, 54, 72, and 108, commonly adventive.

Habitat. Hydrophytic, helophytic, and mesophytic. In water and moist or marshy places, also in disturbed ground and weedy places. Mostly species of open habitats.

Classification. Panicoideae; Paniceae.

Notes. A difficult genus of numerous intergrading forms, its diversity apparently stemming from self-pollination combined with fluent adaptation to a wide range of aquatic and ruderal habits. There is much uncertainty as to how this complex should be divided into species (Clayton and Renvoize, 1986).

Types Species. E. crus-galli (L.) P.Beauv.

Biogeographic Element. Clifford & Simon 1981, Simon & Jacobs 1990: Gondwanan.

Echinopogon Essai Agrost. 42, 148, 161 (1812).

Derivation:. From Greek echinos (hedgehog) and pogon (beard), referring to the very rough awns.

Taxonomic revisions, nomenclatural references:. C.E.Hubbard, Hookers Icones Plantarum 33 .t.3261: 1–7 (1935).

Key references (keys and floras):. G.Bentham, Flora Australiensis 7: 599–600 (1878); C.A.Gardner, Flora of Western Australia 1 Gramineae 147 (1952); E.E.Henty, Manual Grasses New Guinea 84 (1969); J.C.Tothill and J.B.Hacker, Grasses of Southern Queensland 208–209(1983); J.P.Jessop, Flora of South Australia 4: 1921 (1986); B.K.Simon, Key to Australian Grasses 106 (1993); S.W.L.Jacobs and S.M.Hastings, Flora of New South Wales 4: 584–586 (1993); N.G. Walsh, Flora of Victoria 2: 488–489 (1994); D.I.Morris, Student's Flora of Tasmania 4B: 275 (1994); E.Edgar and H.E.Connor, Flora of New Zealand 5: 262–264 (2000); D.Sharp and B.K.Simon, AusGrass (2002); J.P.Jessop, Grasses of South Australia 218–219 (2006);S.W.L.Jacobs, R.D.B.Whalley & D.J.B.Wheeler, Grasses of New South Wales, 4th Ed, 230–233 (2008); A.Wilson (ed.), Flora of Australia 44A: Poaceae 2: 222–228 (2009)

W.D.Clayton & S.A.Renvoize, Genera Graminum (1986), genus (202).

Native. 7 species, from Australia, New Zealand, New Guinea. 7 species in Australia, WA, SA, Qld, NSW, Vic, and Tas. Also Malesia.

Habit. Perennial, rhizomatous or tufted. Leaf blades narrow. Ligule an unfringed membrane.

Inflorescence. Inflorescence paniculate, a spike-like panicle, contracted.

Spikelets. Spikelets laterally compressed, 1 flowered, with 1 fertile floret, solitary, pedicelled; with naked rachilla extension. Fertile spikelets disarticulating above glumes.

Glumes. Glumes relatively large, more or less equal, long relative to adjacent lemmas, pointed (acute to acuminate), awnless, keeled (the keels stiffly ciliate), similar (membranous). Lower glume 1 nerved. Upper glume 1 nerved.

Florets. Fertile florets 1. Lemmas decidedly firmer than glumes (thinly leathery), not becoming indurated, incised, mucronate (E. phleoides) or awned, distinctly 5–7(–11) nerved, glabrous. Awns 1, from a sinus (or slightly behind it), non-geniculate, hairless (scabrid). Palea relatively long, minutely apically notched (3-toothed), 2 nerved, one keeled or not keeled. Lodicules 2. Stamens 3. Grain small, longitudinally grooved, with hairs confined to a terminal tuft. Hilum long-linear. Embryo small.

Kranz Anatomy. C3.

2n = 42.

Habitat. Mesophytic. In open woodland.

Classification. Pooideae; Poeae.

Types Species. E. ovatus (G.Forst.) P.Beauv.

Biogeographic Element. Clifford & Simon 1981, Simon & Jacobs 1990: Australasian.

AVH 2011

Flora of Australia ms

Echinochloa P. Beauv., Echinochloa P.Beauv, Ess. Agrostogr. 53 (1812); from the Greek echinos (hedgehog) and chloa (grass), alluding to the echinate inflorescence branches.

Type: E. crus-galli (L.) P.Beauv.

Annual or perennial, rhizomatous or without rhizomes, stoloniferous or without stolons. Flowering culms erect or decumbent. Leaves; ligule a fringe of hairs or absent; blades  hairy or glabrous, with smooth margins or with scabrous margins. Plants with hermaphrodite florets. Inflorescence a panicle, exserted at maturity or not fully exserted. Primary branches with spikelets appressed to the rachis, distinctly grooved or angled, not winged, scabrous on the margins or relatively smooth on the margins or hairy on the margins. Spikelets with disarticulation at the base of the spikelet, solitary or paired or in clusters, dorsally compressed, lanceolate to obovate. Glumes 2, very unequal, distinctly keeled to rounded on the back; lower glume ovate or elliptic, 1–7 nerved, membranous to chartaceous, acute, muticous or mucronate; upper glume 5–9 nerved, acuminate to acute, muticous or mucronate or awned. Lower floret sterile, or male; lemma membranous to chartaceous, 5 nerved or 7 nerved, strigose, with apex acuminate to acute, awn 0–80 mm long; palea acute or with a rounded apex. Upper floret bisexual, subequal to the lower floret or shorter than the lower floret; lemma yellow, decidedly firmer than glumes, cartilaginous to indurate, smooth, lanceolate to elliptic, the apex sharply differentiated into a membranous green point or the apex gradually differentiated into a membranous green point, acute to acuminate, mucronate or awned; palea cartilaginous to indurate, smooth. Hilum short. 2n = 18, 36,  54, 72, 90, 108 and 126.

A genus of 40–50 species in warm regions; 19 species in Australia, 10 native and 9 introduced, one of the latter possibly with native forms also. This treatment follows the concepts of P.W.Michael & J.W.Vickery (see below).

A difficult genus of numerous intergrading forms, its diversity apparently stemming from self-pollination combined with fluent adaptation to a wide range of aquatic and ruderal habits. There is much uncertainty as to how this complex should be divided into species (Clayton and Renvoize, 1986). The taxonomy of this genus and especially that of E. crus-galli is extremely complicated and not all taxa recognized by some are readily and easily distinguishable. This is caused by easy selfing whereby local races are formed that may be maintained because of ecological adaptations and selection by agricultural practices, e.g. by mechanical or manual harvesting of rice and other cereals, which have selected a number of competitive mimics in grain fields.

Joyce W. Vickery, Echinochloa in Tindale, M.D., Flora of New South Wales No 19. Gramineae, Part 2, 189–211 (1975); P.W. Michael & Joyce W. Vickery, Three new species of Echinochloa from northern Australia. Telopea 2: 25–29 (1980); P.W. Michael, Taxonomy and distribution of Echinochloa species with special reference to their occurrence as weeds of rice, Weed Control in Rice, IRRI, pp 291–306 (1983); W.J.Crins, Echinochloa in The genera of Paniceae (Gramineae: Panicoideae) in the Southeastern United States, 254-262 (1991); P.W.Michael, The taxonomy and distribution of Echinochloa species (barnyard grasses) in the Asian-Pacific region, with a review of pertinent biological studies, Proc. 18th Asian-Pacific Weed Sci Soc.Conf. pp 57–66 (2001); P.W.Michael, Echinochla in M.E.Barkworth, K.M.Capels, S.Long & M.B.Piep (eds.) Flora of North America North of Mexico 25: 390–403 (2003).

Note:- Lengths of the spikelets do not include awns. Colour of caryopses refers only to those which are fully ripe. Chromosome numbers cited are only those which are confidently believed to refer to the species described here.

1 Leaves;  ligule a fringe of long stiff hairs; plants perennial

    2 Spikelets awnless

                           1. *E. pyramidalis

     2: Spikelets mucronate or awned

        3 Spikelets distinctly obovate

                            2. *E. polystachya

         3: Spikelets distinctly ovate

             4 Culms less than 1 m tall; upper leaf blades less than 10 mm wide; ligular hairs absent in uppermost leaves

                                        3. E. picta

              4: Culms to 3.6 m tall; upper leaf blades to 20 mm wide; ligular hairs present in all leaves

                               4.  E. praestans

1: Leaves;  ligule absent or with cilia to 1.5 mm long; plants annual

    5  Inflorescence axis ± smooth; glumes and lower lemma ± smooth

          and lightly scabrous on nerves

                                 5. E. lacunaria

5: Inflorescence axis ± strongly scabrous; glumes and lower lemma

        ± scabrous both on and between nerves

           6  Spikelets at maturity very turgid and subglobose

               7   Spikelets c. 4.5 mm long; lower lemma with a

                        median longitudinal groove

                                6.  E. turneriana

               7:  Spikelets c. 4 mm long; lower lemma without

                             a median longitudinal  groove                                                                                               

             8  Spikelets pallid; caryopsis whitish

                           7. *E. frumentacea

8: Spikelets purplish to blackish‑brown;

                                        caryopsis  brownish

                                 8. *E. esculenta

          6:  Spikelets at maturity less turgid and subglobose

                9 Mature caryopsis 2.5‑3.5 mm long

                     10  Spikelets without well‑developed anthocyanin pigmentation;               upper floret 3.5‑4.5 mm long

                              9. *E. oryzoides

                      10: Spikelets with well‑developed anthocyanin pigmentation; upper floret 4.5‑6.5 mm long

                                11  Upper floret 5‑6.5 mm long; anthers 1.5‑2.1 mm long

                    10. E.  kimberleyensis

                                 11: Upper floret 4.5‑5 mm long; anthers 2.5‑2.8 mm long

                            11. E. macrandra

                9: Mature caryopsis less than 2.5 mm long

                     12 Upper glume noticeably awned

                           13  Upper glume with awns c. 3.5 mm long

                            12. E. dietrichiana

                           13: Upper glume with awns up to 7 mm long

                             14  Inflorescence 20‑35 cm long;

                                                  spikelets 3‑4.2 mm long, with purplish awns

                           13. E. telmatophila                                        

                                     14:  Inflorescence to 15 cm long;

                                          spikelets 4‑4.5 mm long, with pale awns

                                   14. E. elliptica

                     12: Upper glume not or scarcely awned

                         15 Inflorescence drooping with soft flexuous  branches

                                racemes compound; awns curved, up to 15 m m long                                                                                                                                                                 

                        15. *E. crus-pavonis

                         15: Inflorescence usually erect with branches

                                   stiffly spreading; racemes simple

                                      16 Upper floret apex gradually narrowing into a firm tip to 1.5 mm long; awns straight, up to 7 mm long

                                   16.*E. muricata var. microstachya

                                      16: Upper floret apex abruptly terminating

                                                         in a fragile tip to 0.5 mm long

                                                  17 Spikelets 3.5‑5 mm long excluding  cusps and awns when present

                                 17.E. inundata

                                          17:  Spikelets mostly less than 3.5 mm long

                                    18  Spikelets awnless to cuspidate, close together in 4 irregular rows; caryopsis 1.2-1.6 mm long, whitish

                         18.  *E. colona

                                    18: Spikelets awnless to strongly awned, not

                                                     in 4 rows; caryopsis 1.4‑2 mm long,  brownish

                            19. *E. crusgalli


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