| # The grass genera of the world |

L. Watson, T.D. Macfarlane, and M.J. Dallwitz

## Classification

May 1998

Subfamilies, supertribes, tribes and (for Andropogoneae only) subtribes. Genera with 40 or more species indicated by ‘*’; approximate species numbers for tribes, and for genera with 100 or more species, in parentheses. What follows is a brief summary of the classificatory information presented with the individual generic descriptions in this package.

Note that detailed group descriptions complete with statistical data on character state distributions are readily obtainable from the interactive package via the ‘Summary’ command of Intkey (Advanced Mode).

### Stipoideae

Perennial herbs, often caespitose (occasionally ‘bambusoid’). Inflorescence paniculate, espatheate, axes persistent. Spikelets laterally compressed or terete, disarticulating above the glumes, nearly always without incomplete florets, only rarely with a prolonged rachilla. Glumes often equal. Spikelets usually with only one hermaphrodite floret; lemmas not keeled, usually firmer than the glumes, often indurated, without a germination flap; with an apical or sinus-based (often long, geniculate) awn entered by several veins. Paleas mostly 2-nerved, often keel-less. Lodicules rarely absent, often 3, membranous, often heavily vascularized, usually glabrous. Caryopsis nearly always with a long-linear hilum. Embryo small, with an epiblast, scutellar tail and mesocotyl internode absent, embryonic leaf margins meeting (often peculiar in exhibiting a wide angle between coleoptile and coleorhiza). Abaxial leaf blade epidermis. Very rarely papillate. Microhairs rarely present (Lygeum, Nardus); usually absent, but in Stipeae a peculiar (vestigial?) form is sometimes found elsewhere on the plant. Stomatal guard-cells rarely overlapped by the interstomatals. Costal silica bodies often ‘panicoid-type’, crescentic or rounded. Physiology, transverse section of leaf blade. C3. Adaxial surface usually strongly ribbed. Mesophyll with neither fusoids nor arm cells. Midrib usually with a single bundle. Smallest vascular bundles accompanied by sclerenchyma; ‘extra’ sclerenchyma often present. Cytology. Basic chromosome numbers x = (9–)11–12(–13).

Nardeae (1): Nardus.

Lygeae (1): Lygeum.

Ampelodesmeae (1): Ampelodesmos.

Anisopogoneae (1): Anisopogon.

Stipeae (420): *Achnatherum (100?), Aciachne, Anemanthele, *Austrostipa (70), Danthoniastrum (or Aveneae?), Hesperostipa, Lorenzochloa, Jarava, Nassella, Orthachne, Oryzopsis, Piptatherum, Piptochaetium, Psammochloa, Ptilagrostis, *Stipa s. lat. (300), Stipa s. str., Trikeraia.

Brachyelytreae (1): Brachyelytrum (or Bambusoideae?).

### Pooideae

Annual or perennial, herbaceous; culms unbranched above, usually with hollow internodes. Leaf blades not pseudopetiolate, without transverse veins. Ligule an unfringed membrane. Inflorescences various, but not comprising spikelike main branches; espatheate, espatheolate. Spikelets nearly always laterally compressed or terete, with 1–many hermaphrodite florets, rarely with incomplete proximal florets. Lemma without a germination flap. Palea usually 2-keeled and apically notched. Lodicules 2, usually membranous. Stigmas white. Hilum long-linear or short. Embryo small, usually with an epiblast, with neither mesocotyl internode nor scutellar tail, the embryonic leaf margins meeting. Abaxial leaf blade epidermis. Microhairs and papillae absent; costal silica bodies various, but hardly ever ‘panicoid-type’ or saddle-shaped; costal short-cells not in long rows. Stomatal guard-cells overlapped by the interstomatals. Physiology, transverse section of leaf blade. C3. Adaxial surface usually ribbed. Mesophyll with neither fusoids nor arm cells, without colourless columns. Midrib usually with a single vascular bundle. All vascular bundles accompanied by sclerenchyma. Cytology. Basic chromosome number usually x = 7. Group mean diploid 2c DNA value 8.9 pg. Rusts: Puccinia. Smuts: Entyloma, Tilletia, Urocystis, Ustilago.

North and south temperate, tropical mountains (with a Laurasian bias).

#### Triticodae

Inflorescence usually spicate, commonly disarticulating at the joints. Glumes often lateral or ‘displaced’. Lemma awns non-geniculate, usually entered by several veins. Ovary apex hairy, lodicules often ciliate. Endosperm containing only simple starch grains. Abaxial leaf blade epidermis. Crown cells sometimes present; stomata often very large. Cytology. Group mean diploid 2c DNA value 10.6 pg.

Triticeae (360): Aegilops, Agropyron, Amblyopyrum, Australopyrum, Cockaynea, Crithopsis, Dasypyrum, *Elymus (150), Elytrigia, Eremopyrum, Festucopsis, Henrardia, Heteranthelium, Hordelymus, *Hordeum, Hystrix, Kengyilia, Leymus, Lophopyrum, Malacurus, Pascopyrum, Peridictyon, Psathyrostachys, Pseudoroegneria, Secale, Sitanion, Taeniatherum, Thinopyrum, Triticum.

Brachypodieae (16): Brachypodium.

Bromeae (150): Boissiera, *Bromus.

#### Poodae

Inflorescence usually paniculate with persistent axes, or a persistent spike. Spikelets usually disarticulating above the glumes. Lemma awn geniculate or straight, entered by only one vein. Ovary apex usually glabrous; lodicules usually glabrous. Endosperm usually containing compound starch grains. Group mean 2c DNA value 7.9 pg.

Aveneae (including Agrostideae, Phalarideae; dubiously separable from the Poeae) (1050): *Agrostis (220), Aira, Airopsis, Alopecurus, Ammochloa, Ammophila, Amphibromus, Ancistragrostis, Aniselytron, Anthoxanthum, Antinoria, Apera, Arrhenatherum, Avellinia, Avena, Beckmannia, *Calamagrostis (230), Chaetopogon, Cinna, Cornucopiae, Corynephorus, Cyathopus, Danthoniastrum (or Stipeae?), *Deschampsia, Deyeuxia, Dichelachne, Dielsiochloa, Duthiea (or Danthonieae?), Echinopogon, Euthryptochloa, Gastridium, Gaudinia, Gaudiniopsis, Graphephorum, *Helictotrichon, Hierochloë, Holcus, Hyalopoa, Hypseochloa, *Koeleria, Lagurus, Leptagrostis, Libyella, Limnas, Limnodea, Linkagrostis, Maillea, Metcalfia (or Danthonieae?), Mibora, Milium, Nephelochloa, Pentapogon, Periballia, Peyritschia, Phalaris, Phleum, Pilgerochloa, Polypogon, Pseudarrhenatherum, Pseudodanthonia (or Danthonieae?), Pseudophleum, Relchela, Rhizocephalus, Scribneria, Sinochasea, Sphenopholis, Stephanachne, Stilpnophleum, Tovarochloa, Triplachne, *Trisetum, Vahlodea, Ventenata, Zingeria. Upper glume nearly always long relative to the adjacent lemma; female-fertile florets 1–2(–7).

Poeae (including Hainardieae, Monermeae; dubiously separable from the Aveneae) (1124): Agropyropsis, Anthochloa, Aphanelytrum, Arctagrostis, Arctophila, Austrofestuca, Bellardiochloa, Briza, Calosteca, Castellia, Catabrosella, Catapodium, Coleanthus, Colpodium, Ctenopsis, Cutandia, Cynosurus, Dactylis, Dasypoa, Desmazeria, Dissanthelium, Dryopoa, Dupontia, Eremopoa, Erianthecium, *Festuca (360), Festucella, Gymnachne, Hainardia, Helleria, Hookerochloa, Lamarckia, Leucopoa, Lindbergella, Littledalea, Loliolum, Lolium, Lombardochloa, Megalachne, Microbriza, Micropyropsis, Micropyrum, Narduroides, Parafestuca, Parapholis, Phippsia, Pholiurus, *Poa (500), Podophorus, Poidium, Pseudobromus, Psilurus, *Puccinellia, Rhomboelytrum, Sclerochloa, Scolochloa, Simplicia, Sphenopus, Torreyochloa, Tsvelevia, Vulpia, Vulpiella, Wangenheimia. Glumes usually short relative to adjacent lemma; female-fertile florets (1–)2–many.

Seslerieae (33): Echinaria, Oreochloa, Psilathera, Sesleria, Sesleriella.

Meliceae (136): Brylkinia, Catabrosa, *Glyceria, Lycochloa, *Melica, Pleuropogon, Schizachne, Streblochaete, Triniochloa. Leaf sheath margins joined. Basic chromosome number x = 9 or 10.

### Bambusoideae

Mostly perennial, culms woody or herbaceous. Leaf blades often pseudopetiolate, often with transverse veins, often disarticulating. Inflorescence usually paniculate, often spatheate. Lemmas with non-geniculate awns or awnless. Palea keel-less, 1- or 2-keeled, notched or entire. Lodicules 1–10 (often 3). Hilum usually long-linear. Embryo usually small, with an epiblast, usually with a scutellar tail and overlapping leaf margins. Abaxial leaf blade epidermis. Microhairs present, panicoid type. Papillae often present. Costal silica bodies often ‘panicoid-type’, ‘oryzoid-type’ or saddle-shaped. Stomatal subsidiaries usually triangular or dome-shaped. Physiology, transverse section of leaf blade. C3. Adaxial surface often flat. Mesophyll commonly with arm-cells and/ or fusoids. Midrib usually with more than one vascular bundle, often with complex vasularization. All vascular bundles accompanied by sclerenchyma. Cytology. Chromosome base number usually x = 10, 11 or 12. Rusts: Dasturella, Physopella, Stereostratum, Puccinia. Smuts: Entyloma, Tilletia, Sorosporium, Tolyposporium, Ustilago.

Tropical/ warm temperate, mostly forest/ woodland and wet places.

#### Oryzodae

‘Grasses’, or to varying degrees more or less bambusoid in appearance; mostly herbaceous, culms commonly unbranched above. Lodicules commonly 2, rarely ciliate. Stigmas usually 2. Mesophyll with or without arm-cells and/ or fusoids. Mostly diploids. Group mean diploid 2c DNA value 3.0 pg.

Oryzeae (73): Chikusichloa, Hydrochloa, Hygroryza, Leersia, Luziola, Maltebrunia, Oryza, Porteresia, Potamophila, Prosphytochloa, Rhynchoryza, Zizania, Zizaniopsis. Spikelets laterally compressed, with one hermaphrodite floret and sometimes with a proximal sterile lemma. Glumes absent or reduced to a minute cupule. Hilum long-linear. Mostly hydrophytic or helophytic.

Olyreae (120): Agnesia, Arberella, Buergersiochloa, Cryptochloa, Diandrolyra, Ekmanochloa, Froesiochloa, Lithachne, Maclurolyra, Mniochloa, Olyra, Pariana, Parodiolyra, Piresia, Piresiella, Raddia, Raddiella, Rehia, Reitzia, Sucrea. Monoecious, the spikelets mixed or in separate inflorescences. Female spikelets usually dorsally compressed, with well developed glumes and one floret; lemma hard, usually with a germination flap.

Anomochloeae (1): Anomochloa.

Diarrheneae (4–5): Diarrhena (or Stipoideae?).

Ehrharteae (44): Ehrharta, Microlaena, Petriella, Tetrarrhena. Spikelets compressed laterally or terete; with two proximal sterile florets and one hermaphrodite floret.

Phaenospermateae (1): Phaenosperma.

Phyllorhachideae (3): Humbertochloa, Phyllorhachis.

Phareae (14): Leptaspis, Pharus, Scrotochloa, Suddia.

Streptochaeteae (2): Streptochaeta.

Streptogyneae (2): Streptogyna.

#### Bambusodae

Woody bamboos with branching culms. Lodicules usually 3 or more, ciliate. Stigmas usually 3 or more. Usually tetraploid or hexaploid.

Guaduelleae (8): Guaduella.

Puelieae (6): Puelia.

Bambuseae (825): Acidosasa, Actinocladum, Alvimia, Apoclada, Arthrostylidium, *Arundinaria, Athroostachys, Atractantha, Aulonemia, *Bambusa (120), Cephalostachyum, Chimonobambusa, *Chusquea (100), Davidsea, Colanthelia, Decaryochloa, Dendrocalamus, Dendrochloa, Dinochloa, Elytrostachys, Fargesia, Gigantochloa, Glaziophyton, Greslania, Hickelia, Hitchcockella, Indocalamus, Indosasa, Melocalamus, Melocanna, *Merostachys, Metasasa, Monocladus, Myriocladus, Nastus, Neohouzeaua, Neurolepis, Ochlandra, Olmeca, Oreobambos, Otatea, Oxytenanthera, Perrierbambus, *Phyllostachys, Pseudocoix, Pseudosasa, Pseudostachyum, Pseudoxytenanthera, Racemobambos, Rhipidocladum, *Sasa, Schizostachyum, Semiarundinaria, Shibataea, *Sinarundinaria, Sinobambusa, Sphaerobambos, Swallenochloa, Teinostachyum, Thamnocalamus, Thyrsostachys, Vietnamosasa, Yushania.

### Centothecoideae

Perennial herbs (raely woody), leaf blades broad and mostly cross veined, often pseudopetiolate but rarely disarticulating; ligule a fringed or unfringed membrane. Inflorescences espatheate; racemes, of spicate branches, or panicles, the axes persistent. Spikelets compressed laterally, with 1–12(–17) hermaphrodite florets, with an apically prolonged rachilla, with incomplete florets apically or both apically and basally, disarticulating above or below the glumes. Lemmas usually awnless. Paleas 2 nerved and 2 keeled. Lodicules (when present) 2, fleshy, glabrous. Caryopsis with simple starch grains, a short, punctate hilum. Embryo small, with an epiblast, scutellar tail and elongated mesocotyl internode and (usually) overlapping first leaf margins. Abaxial leaf blade epidermis. Papillae absent. Microhairs present, panicoid-type. Stomatal guard-cells not overlapped by the interstomatals. Costal silica bodies panicoid-type. Physiology, transverse section of leaf blade. C3. Midrib conspicuous. Adaxial palisade often present. Arm-cells only rarely present, but the outer bundle sheaths often exhibiting much enlarged lateral cells reminiscent of fusoids. Cytology. Basic chromosome number usually x = 12.

Centotheceae (33): Bromuniola, Calderonella, Centotheca, Chasmanthium, Chevalierella, Gouldochloa, Lophatherum, Megastachya, Orthoclada, Pohlidium, Zeugites.

### Arundinoideae

Perennial herbs, often caespitose (sometimes ‘bambusoid’). Leaf blades sometimes disarticulating. Ligule usually a fringed membrane or a fringe of hairs. Inflorescence usually paniculate, espatheate, axes persistent. Spikelets usually laterally compressed or terete and disarticulating above the glumes; with 1–many hermaphrodite florets, occasionally with proximal incomplete florets. Lemmas usually hairy, incised, usually awned, awns straight or geniculate. Palea usually 2-nerved and 2-keeled. Lodicules fleshy or membranous, ciliate or glabrous. Stigmas 2. Endosperm usually with compound starch grains. Abaxial leaf blade epidermis. Microhairs present or absent (then usually present somewhere on the plant). Non-papillate. Costal silica bodies of various forms, but hardly ever ‘pooid-type’. Stomatal guard-cells usually not overlapped by the interstomatals; subsidiaries usually triangular to dome-shaped. Physiology, transverse section of leaf blade. C3 or C4 type NADP–ME. Adaxial surface usually ribbed. Mesophyll without fusoids, very rarely with arm-cells. Midrib usually with a single bundle. Smallest vascular bundles accompanied by sclerenchyma. Cytology. Chromosome base numbers variable. Rusts: Dasturella, Puccinia. Smuts: Neovossia, Tilletia, Urocystis, Sorosporium, Sphacelotheca, Tolyposporium, Ustilago.

Cosmopolitan, but with a marked Gondwanan bias.

Steyermarkochloeae (2): Arundoclaytonia, Steyermarkochloa.

Arundineae (7): Arundo, Dichaetaria (or crinipoid Danthonieae?), Gynerium(?), Hakonechloa, Molinia, Phragmites, Thysanolaena (or Centothecoideae?). Helophytes and mesophytes of moist places, including tall reeds, sometimes woody. Leaf blades usually disarticulating, ligule a fringed membrane or a fringe of hairs; contraligules common. Inflorescence a non-spatheate panicle, branches persistent. Spikelets laterally compressed, disarticulating above the glumes, with a prolonged rachilla and 1-10 female-fertile florets; incomplete florets distal, or distal and proximal. Lemmas entire, non-carinate. Lodicules 2, usually fleshy and glabrous. Embryo usually large, without an epiblast, scutellar tail present, mesocotyl internode elongated, first leaf margins meeting. Synergids not haustorial. Abaxial leaf blade epidermis. Papillae absent. Microhairs present (but often rare), panicoid type. Stomatal guard-cells not overlapped. Physiology, transverse section of leaf blade. C3. No adaxial palisade. Arm cells sometimes present, fusoids absent (except perhaps in Hakonechloa). Sclerenchyma all bundle-associated. Basic chromosome number x = 11–12 or 9

Danthonieae (315): Alloeochaete, Centropodia, Chaetobromus, Chionochloa, Cortaderia, Crinipes, Danthonia, Danthonidium, Dregeochloa, Duthiea (or Aveneae?), Elytrophorus, Erythranthera, Habrochloa, Karroochloa, Lamprothyrsus, Merxmuellera, Metcalfia (or Aveneae?), Monachather (or Arundineae?), Monostachya, Nematopoa, Notochloë, Pentameris, *Pentaschistis, Phaenanthoecium, Plinthanthesis, Poagrostis, Prionanthium, Pseudodanthonia (or Aveneae?), Pseudopentameris, Pyrrhanthera, *Rytidosperma, Schismus, Sieglingia, Styppeiochloa, Tribolium, Urochlaena, Zenkeria. Mostly less than 250 cm high. Spikelets with 2–many hermaphrodite florets, without proximal incomplete florets. Nearly all C3 (exception Centropodia).

Cyperochloeae (1): Cyperochloa.

Micrairieae (13): Micraira.

Spartochloeae (1): Spartochloa.

Aristideae (344): *Aristida (290), Sartidia, *Stipagrostis. Spikelets with one hermaphrodite floret, no incomplete florets. Lemma hardened, with or without a germination flap; with a characteristic trifid awn (or derivative of this). Palea reduced. C3 (Sartidia) or C4. Chromosome base number usually 11.

Eriachneae (42): *Eriachne, Pheidochloa. Ligule a fringe of hairs; inflorescence a panicle or raceme; lower glume (7–)9–15 nerved; spikelets without proximal incomplete florets; female-fertile florets (1–)2; hilum long-linear. XyMS+; C4, type NADP-ME.

Amphipogoneae (9): Amphipogon, Diplopogon. Inflorescence spicate or contracted; spikelets usually compressed dorsiventrally to terete; lemma deeply cleft into three apically awned lobes; palea with two apical awns or setae; pericarp free (opaque). Microhairs Enneapogon-type.

### Chloridoideae

Culms herbaceous, branched or unbranched above. Leaf blades not pseudopetiolate. Ligule nearly always a fringed membrane or of hairs. Inflorescences various, commonly of dorsiventral, spikelike main branches or paniculate, espatheate; axes usually persistent. Sometimes dioecious or monoecious with unisexual spikelets, usually with hermaphrodite spikelets and hermaphrodite florets. Female-fertile spikelets usually disarticulating above the glumes, compression lateral to dorsiventral; lower glume usually 1-nerved; very rarely with proximal incomplete florets; hermaphrodite (or female) florets 1–many. Lemmas without a germination flap, awn if present non-geniculate. Palea 2-nerved and 2-keeled. Lodicules 2, fleshy, glabrous. Pericarp often free or loose. Hilum short. Embryo large; usually with an epiblast; scutellar tail and mesocotyl internode present, embryonic leaf margins meeting. Abaxial leaf blade epidermis. Microhairs present, chloridoid type or (less often) panicoid type. Costal silica-bodies mostly panicoid-type or saddle shaped, the costal short-cells in long rows. Stomatal guard-cells not overlapped by the interstomatals; subsidiaries triangular to dome-shaped. Physiology, transverse section of leaf blade. Exclusively C4 , with the only known exception (Eragrostis walteri) probably belonging in the Arundinoideae; types PCK and NAD–ME (all XyMS+). Adaxial surface often flat. Mesophyll often traversed by colourless columns; fusoids absent, arm-cells (nearly always) absent. Bulliforms commonly combined with colourless cells to form deep-penetrating fans. Smallest vascular bundles accompanied by sclerenchyma. Cytology. Chromosome base number usually x = 10. Group mean 2c DNA value 1.1 pg. Rusts: Physopella, Puccinia. Smuts: Entyloma, Melanotaenium, Tilletia, Sorosporium, Sphacelotheca, Tolyposporella, Ustilago. Mostly tropical and subtropical (especially Old World and Gondwanan), especially dry climates.

Triodieae (54): Monodia, Plectrachne, Symplectrodia, Triodia.

Pappophoreae (41): Cottea, Enneapogon, Kaokochloa, Pappophorum Schmidtia.

Orcuttieae (9): Neostapfia, Orcuttia, Tuctoria.

Main chloridoid assemblage (including Chlorideae, Cynodonteae, Eragrosteae, Sporoboleae, Aeluropodeae, Jouveae, Unioleae, Leptureae, Lappagineae, Spartineae, Trageae, Perotideae, Pommereulleae) (1305): Acamptoclados, Acrachne, Aegopogon, Aeluropus, Afrotrichloris, Allolepis, Apochiton, Astrebla, Austrochloris, Bealia, Bewsia, Blepharidachne, Blepharoneuron, *Bouteloua, Brachyachne, Brachychloa, Buchloë, Buchlomimus, Calamovilfa, Catalepis, Cathestechum, Chaetostichium, Chaboissaea, *Chloris, Chrysochloa, Cladoraphis, Coelachyropsis, Coelachyrum, Craspedorhachis, Crypsis, Ctenium, Cyclostachya, Cynodon, Cypholepis, Dactyloctenium, Daknopholis, Dasyochloa, Decaryella, Desmostachya, Diandrochloa, Dignathia, Dinebra, Diplachne, Distichlis, Drake-Brockmania, Ectrosia, Ectrosiopsis, Eleusine, Enteropogon, Entoplocamia, Eragrostiella, *Eragrostis (350), Erioneuron, Eustachys, Farrago, Fingerhuthia, Gouinia, Griffithsochloa, Gymnopogon, Halopyrum, Harpachne, Harpochloa, Heterachne, Heterocarpha, Hilaria, Hubbardochloa, Indopoa, Ischnurus, Jouvea, Kampochloa, Kengia, Leptocarydion, Leptochloa, Leptochloöpsis, Leptothrium, Lepturella, Lepturidium, Lepturopetium, Lepturus, Lintonia, Lophacme, Lopholepis, Lycurus, Melanocenchris, Microchloa, Monanthochloë, Monelytrum, Mosdenia, *Muhlenbergia (160), Munroa, Myriostachya, Neeragrostis, Neesiochloa, Neobouteloua, Neostapfiella, Neyraudia, Ochthochloa, Odyssea, Opizia, Orinus, Oropetium, Oxychloris, Pentarrhaphis, Pereilema, Perotis, Piptophyllum, Planichloa, Pogonarthria, Pogoneura, Pogonochloa, Polevansia, Pommereulla, Pringleochloa, Psammagrostis, Pseudozoysia, Psilolemma, Pterochloris, Redfieldia, Reederochloa, Rendlia, Richardsiella, Saugetia, Schaffnerella, Schedonnardus, Schenckochloa, Schoenefeldia, Sclerodactylon, Scleropogon, Silentvalleya, Soderstromia, Sohnsia, Spartina, *Sporobolus (160), Steirachne, Stiburus, Swallenia, Tetrachaete, Tetrachne, Tetrapogon, Thellungia, Tragus, Trichoneura, Tridens, Triplasis, Tripogon, Triraphis, Uniola, Urochondra, Vaseyochloa, Vietnamochloa, Viguierella, Willkommia, Zoysia.

### Panicoideae

Culms mostly herbaceous, usually branching above, internodes more often solid than hollow. Ligule a fringed or unfringed membrane, or a fringe of hairs. Inflorescence commonly paniculate, equally commonly of spikelike main branches (these often dorsiventral), spatheate or not; the axes disarticulating or persistent. Sometimes dioecious or monoecious, or with hermaphrodite spikelets. Female-fertile spikelets usually compressed dorsiventrally and falling with the glumes; rachilla not prolonged apically; nearly always with one proximal incomplete (male or sterile) floret and one hermaphrodite (rarely female-only) floret. Lodicules fleshy, usually glabrous. Stigmas usually red-pigmented. Hilum usually short. Endosperm starch grains usually simple. Embryo usually large; without an epiblast; scutellar tail and mesocotyl internode present; embryonic leaf margins overlapping. Abaxial leaf blade epidermis. Microhairs present, panicoid-type. Costal silica-bodies nearly always ‘panicoid-type’ (horizontally-elongated, cross-shaped, dumb-bell shaped or nodular); costal short-cells in long rows. Sometimes papillate. Stomatal guard-cells not overlapped by the subsidiaries; subsidiaries triangular or dome-shaped. Physiology, transverse section of leaf blade. C3 or C4. Adaxial surface often flat. Mesophyll without arm-cells, very rarely with fusoids. Midrib usually with an arc of bundles, often with adaxial colourless tissue. Smallest bundles commonly unaccompanied by sclerenchyma. Cytology. Chromosome base numbers mostly x = 5, 9 or 10. Group mean diploid 2c DNA value 3.0 pg. Rusts: Dasturella, Phakopsora, Physopella, Puccinia. Smuts: Entyloma, Melanotaenium, Tilletia, Sorosporium, Sphacelotheca, Tolyposporella, Tolyposporium, Ustilago.

Mainly tropical (especially Old World and Gondwanan), extending to temperate.

#### Panicodae

Inflorescence usually espatheate, the axes persistent or condensed into deciduous spikelet clusters. Spikelets sometimes in long-and-short combinations, but usually all alike in form and sexuality. Female-fertile lemma firm or indurated, with a germination flap, usually awnless and entire; the palea well developed. C3 or C4 (occasionally intermediate), types PCK, NAD–ME and NADP–ME (the latter all XyMS–). Basic chromosome number usually x = 9. Pantropical to temperate; diverse habitat and rainfall requirements.

Isachneae (126): Coelachne, Cyrtococcum, Heteranthoecia, Hubbardia, *Isachne (100), Limnopoa, Sphaerocaryum. Usually with both florets female-fertile; C3.

Paniceae (about 2000): Achlaena, Acostia, Acritochaete, Acroceras, Alexfloydia, Alloteropsis, Amphicarpum, Ancistrachne, Anthaenantiopsis, Anthenantia, Anthephora, Arthragrostis, Arthropogon, *Axonopus (110), Baptorhachis, Beckeropsis, Boivinella, *Brachiaria (100), Calyptochloa, Camusiella, Cenchrus, Centrochloa, Chaetium, Chaetopoa, Chamaeraphis, Chasechloa, Chloachne, Chlorocalymma, Cleistochloa, Cliffordiochloa, Commelinidium, Cymbosetaria, Cyphochlaena, Dallwatsonia, *Dichanthelium (120), *Digitaria (220), Digitariopsis, Dimorphochloa, Dissochondrus, Eccoptocarpha, *Echinochloa, Echinolaena, Entolasia, Eriochloa, Fasciculochloa, Gerritea, Holcolemma, Homolepis, Homopholis, Hydrothauma, Hygrochloa, Hylebates, Hymenachne, Ichnanthus, Ixophorus, Lasiacis, Lecomtella, Leptocoryphium, Leptoloma, Leucophrys, Louisiella, Megaloprotachne, Melinis, Mesosetum, Microcalamus, Mildbraediochloa, Odontelytrum, Ophiochloa, Oplismenopsis, Oplismenus, Oryzidium, Otachyrium, Ottochloa, *Panicum (370), Paratheria, Parectenium, *Paspalidium, *Paspalum (320), *Pennisetum, Perulifera, Plagiantha, Plagiosetum, Poecilostachys, Pseudechinolaena, Pseudochaetochloa, Pseudoraphis, Reimarochloa, Reynaudia, Rhynchelytrum, Sacciolepis, Scutachne, *Setaria (110), Setariopsis, Snowdenia, Spheneria, Spinifex, Steinchisma, Stenotaphrum, Stereochlaena, Streptolophus, Streptostachys, Taeniorhachis, Tarigidia, Tatianyx, Thrasya, Thrasyopsis, Thuarea, Thyridachne, Trachys, Tricholaena, Triscenia, Uranthoecium, Urochloa, Whiteochloa, Xerochloa, Yakirra, Yvesia, Zygochloa. C3, or C4 type PCK, NAD–ME and NADP–ME.

Neurachneae (10): Neurachne, Paraneurachne, Thyridolepis. Inflorescence a single spicate raceme. C3, C4 type NADP–ME (XyMS–) or intermediate.

Arundinelleae (184): *Arundinella, Chandrasekharania, Danthoniopsis, Diandrostachya, Dilophotriche, Garnotia, Gilgiochloa, Isalus, Jansenella, Loudetia, Loudetiopsis, Trichopteryx, Tristachya, Zonotriche. Spikelets compressed laterally to terete, disarticulating above the glumes. Lemma usually bilobed or cleft, usually with a geniculate awn. Hilum usually long-linear. C4 type NADP–ME (XyMS–, often with isolated PCR cells), or rarely C3 (?). Chromosome base number x = 10 or 12.

#### Andropogonodae

Inflorescence often spatheate and/ or spatheolate, the axes usually disarticulating. Spikelets usually in long-and-short combinations, often heterogamous, the members of the combinations different in sexuality (the longer-pedicelled members usually male or sterile). Glumes usually very dissimilar. The female-fertile lemma usually reduced to a stipe, insubstantial or hyaline; often bifid, with a geniculate awn; without a germination flap. Palea commonly reduced, vestigeal or absent. Exclusively C4, type NADP–ME (XyMS–). Chromosome base number, x = mostly 5 or 10. Tropical/ warm temperate; mostly requiring seasonal high rainfall.

Andropogoneae (967):

Plants usually bisexual with hermaphrodite (upper) florets. Lodicules usually present.

Andropogoninae (inflorescences mostly ‘racemes’ with slender rachides, articles without a basal callus knob and commonly hairy; dispersal unit usually with a basal, hairy callus; proximal incomplete floret usually sterile; female-fertile lemma very often incised or cleft, usually awned; female-fertile palea often absent, otherwise generally relatively short or much reduced, commonly nerveless. Abaxial leaf blade epidermis commonly papillate; stomata 18–30–60 microns long; intercostal short-cells often absent or very rare, when present often solitary): Agenium, Anadelphia, *Andropogon (100), Andropterum, Apluda, Apocopis, Arthraxon, Asthenochloa, Bhidea, Bothriochloa, Capillipedium, Chrysopogon, Chumsriella, Clausospicula, Cleistachne, *Cymbopogon, Dichanthium, Diectomis, Digastrium, Diheteropogon, *Dimeria, Dybowskia, Eccoilopus, Elymandra, Eremopogon, Erianthus, Eriochrysis, Euclasta, Eulalia, Eulaliopsis, Exotheca, Germainia, Hemisorghum, Heteropogon, Homozeugos, *Hyparrhenia, Hyperthelia, Hypogynium, Imperata, *Ischaemum, Ischnochloa, Iseilema, Kerriochloa, Lasiorhachis, Leptosaccharum, Lophopogon, Microstegium, Miscanthidium, Miscanthus, Monium, Monocymbium, Narenga, Parahyparrhenia, Pleiadelphia, Pobeguinea, Pogonachne, Pogonatherum, Polliniopsis, Polytrias, Pseudanthistiria, Pseudodichanthium, Pseudopogonatherum, Pseudosorghum, Saccharum, *Schizachyrium, Sclerostachya, Sehima, Sorghastrum, Sorghum, Spathia, Spodiopogon, Thelepogon, Themeda, Trachypogon, Triplopogon, Vetiveria, Ystia.

Rottboelliinae (infloresences with substantial rachides, mostly spikelike, commonly with spikelets more or less embedded and/ or the pedicels more or less fused; articles mostly glabrous, nearly always non-linear and with a basal callus knob (elaiosome), usually without a hairy callus; proximal incomplete floret often male; female-fertile lemma entire, awnless; female-fertile palea present, often relatively long, often binerved. Abaxial leaf blade epidermis very rarely papillate; stomata 22–40–63 microns long; paired intercostal short-cells usually common): Chasmopodium, Coelorachis, Elionurus, Eremochloa, Glyphochloa, Hackelochloa, Hemarthria, Heteropholis, Jardinea, Lasiurus, Lepargochloa, Loxodera, Manisuris, Mnesithea, Ophiuros, Oxyrhachis, Phacelurus, Pseudovossia, Ratzeburgia, Rhytachne, Robynsiochloa, Rottboellia, Thaumastochloa, Thyrsia, Urelytrum, Vossia.

Maydeae (32): Chionachne, Coix, Euchlaena, Polytoca, Sclerachne, Trilobachne, Tripsacum, Zea. Plants monoecious, with all the fertile spikelets unisexual; without hermaphrodite florets. The male and female-fertile spikelets in different inflorescences, on different branches of the same inflorescence, or on different parts of the same branch. Lodicules absent.

Revised 3 August 2019

Contents