Poaceae Barnhart

Gramineae, W. D. Clayton. Flora of Tropical East Africa. 1970

Morphology General Habit

Annual or perennial herbs, rarely shrubs or trees, sometimes with rhizomes or stolons; stems erect, ascending or creeping, usually branched at the base, in perennials with sterile shoots and flowering stems (culms) mixed, in annuals only the latter present; culms cylindrical, rarely flattened, jointed, usually hollow in the internodes, closed at the nodes; branches subtended by a leaf, and with a 2-keeled hyaline leaflet (prophyll) at the base

Morphology Leaves

Leaves solitary at the nodes, sometimes crowded at the base of the stem, alternate and 2-rowed, consisting of sheath, ligule and blade (fig. 1, p. 3); sheaths encircling the culm, with the margins free and overlapping or ± connate, frequently swollen at the base, the shoulders sometimes extended upwards into triangular auricles; ligule adaxial, placed at the junction of sheath and blade, membranous or reduced to a fringe of hairs, rarely absent (very rarely with a similar abaxial structure—the external ligule); blades usually long and narrow, rarely broad, flat or sometimes rolled or terete, parallel-nerved, rarely with transverse connections, usually passing gradually into the sheath, sometimes amplexicaul or with falcate auricles, rarely narrowed into a false petiole or articulated with the sheath

Morphology Reproductive morphology Inflorescences

Spikelets (fig. 1) consisting of bracts distichously arranged along a slender axis (rhachilla); the 2 lower bracts (glumes) empty; the succeeding 1 to many bracts (lemmas) each enclosing a flower and opposed by a hyaline scale (palea), the whole (lemma, palea and flower) termed a floret; base of spikelet or floret sometimes with a horny prolongation downwards (callus); glumes or lemmas often bearing 1 or more stiff bristles (awns); this basic pattern of spikelet structure consistent throughout the family, though often much modified by reduction, suppression or elaboration of parts Inflorescences made up of spikelets arranged in a panicle, or in spikes or racemes, these either solitary, digitate, or disposed along a central axis, usually terminal, sometimes (especially in Andropogoneae) numerous, each inflorescence being subtended by a bladeless sheath (spatheole) and the whole flowering branch system condensed into a leafy false panicle

Morphology Reproductive morphology Flowers

Flowers usually hermaphrodite, sometimes unisexual, small and inconspicuous; perianth represented by 2, rarely 3, minute hyaline or fleshy scales (lodicules); stamens hypogynous, 1–6, rarely more, usually 3, with delicate filaments and 2-thecous anthers opening by a longitudinal slit or rarely a terminal pore; ovary 1-locular, with 1 anatropous ovule often adnate to the adaxial side of the carpel; styles usually 2, rarely 1 or 3, generally with plumose stigmas

Morphology Reproductive morphology Fruits

Fruit mostly a caryopsis with thin pericarp adnate to the seed, rarely with free seed, still more rarely a nut or berry; caryopsis commonly combined with various parts of the spikelet, or less often the inflorescence, to form a false fruit; seed with starchy endosperm, an embryo at the base of the abaxial face, and a point or line (hilum) on the base or adaxial face marking the connection between pericarp and seed

Gemma Bramley, Anna Trias-Blasi & Richard Wilford (2023). The Kew Temperate Plant Families Identification Handbook. Kew Publishing Royal Botanic Gardens, Kew

Recognition

Characters of similar families: Cyperaceae: culms 3-sided, leaves usually 3-ranked, flowers minute, perianth reduced to bristles, rarely tepals, or 0, fruit a 1-seeded nutlet. Juncaceae: stems rounded and without nodes, flowers mostly hermaphrodite, minute and regular, perianth of 6 tepals, fruit a capsule with 3–many seeds. Restionaceae: plants mostly dioecious, leaves usually reduced to sheaths, flowers mostly unisexual, minute and regular, perianth of 6 tepals, fruit a 1–3-locular capsule or nutlet.

Morphology General Habit

Herbs, rhizomatous, stoloniferous or annual, sometimes woody (bamboos)

Morphology Culms

Culms rounded or flattened, often hollow, noded

Morphology Leaves

Leaves solitary at the nodes, sometimes crowded at the base of the stem, alternate and usually in 2 ranks, consisting of sheath, ligule and blade; sheath with margins free and overlapping or, rarely, more or less fused; ligule at junction of blade and sheath, membranous, a row of hairs, rarely absent; blade usually linear, rarely broad and short, flat, rolled or folded, parallel-veined

Morphology Reproductive morphology Inflorescences

Inflorescence comprising spikelets arranged in open or contracted panicles, racemes or spikes

Morphology Reproductive morphology Inflorescences Spikelets

Spikelets of 1–many flowers (florets), distichous, sessile on a slender axis (the rachilla), subtended by 2 (rarely 1) empty glumes

Morphology Reproductive morphology Flowers Florets

Florets mostly bisexual, sometimes unisexual or sterile, usually with ovary, stamens, and 2–3 minute fleshy scales (lodicules), the whole between 2 bracts that are known as the lemma (the lower bract) and the palea

Morphology Reproductive morphology Flowers Androecium Stamens

Stamens 1–6 but most commonly 3

Morphology Reproductive morphology Flowers Gynoecium Stigma

Stigmas usually 2, plumose

Morphology Reproductive morphology Fruits

Fruit a caryopsis, with the pericarp adhering to the seed.

Distribution

About 760 genera and 12,000 species. Worldwide, including Antarctica.

Ecology

Poaceae are dominant components of many non-forest ecosystems.

Note

Rhizomatous, stoloniferous or annual, sometimes woody herbs. Culms noded. Leaves 2-ranked, ligule present. Inflorescence with spikelets in open or contracted panicles, racemes or spikes. Lemma and palea present as part of a floret. Fruit a caryopsis.

Description Author

David A Simpson & Martin Xanthos

George R. Proctor (2012). Flora of the Cayman Isands (Second Edition). Royal Botanic Gardens, Kew

Morphology General Habit

Annual or perennial herbs, rarely woody or tree-like

Morphology Stem

Stems (culms) usually terete and hollow (rarely solid), with closed nodes

Morphology Leaves

Leaves 2-ranked, usually elongate, with a distinct basal sheath split on one side to the point of attachment, and a small appendage (the ligule) at the junction of sheath and blade

Morphology Reproductive morphology Inflorescences

Inflorescence a spike, raceme or panicle of densely or loosely aggregated spikelets, each spikelet consisting of a rhachilla bearing 1–several flowers subtended by small bractlets; the lowest 2 bractlets (glumes) sterile; each succeeding bractlet (lemma) enclosing a flower, with another bractlet (palea) subtending the flower on the upper side

Morphology Reproductive morphology Flowers

Flowers perfect or unisexual-Perianth none, or reduced to 2 or 3 minute scales (lodicules)

Morphology Reproductive morphology Flowers Androecium Stamens

Stamens 1–6 (usually 3), separate; anthers 2-locular, attached at the middle

Morphology Reproductive morphology Flowers Gynoecium Ovary

Ovary superior, 1-locular with 1 ovule; styles 1–3 (usually 2), more or less plumose

Morphology Reproductive morphology Fruits

Fruit a seed-like grain (caryopsis); endosperm copious, starchy.

Distribution

A large, world-wide family of about 750 genera and more than 9000 species (some authorities estimate as many as 10,000).

Note

This is economically the most important family of plants. Because of the complexity of classification, it is customary to arrange grasses in groups called tribes, and this practice was followed in the First Edition of this Flora, following the system presented by Hitchcock (1936). However, grass taxonomy has undergone so much change in recent years that in the present book, the genera are arranged alphabetically without reference to tribal position.

Milliken, W., Klitgard, B. and Baracat, A. (2009 onwards), Neotropikey - Interactive key and information resources for flowering plants of the Neotropics. http://creativecommons.org/licenses/by/3.0

Morphology General Habit

Annual or perennial, less commonly sublignified to lignified plants, caespitose, rhizomatous or stoloniferous

Morphology Leaves

Leaves alternate, distichous, leaf-sheaths open, less commonly closed, adaxial ligule generally present, membranaceous to pilose, leaf-blades linear to lanceolate, less frequently ovate to oblong - lanceolate, and with a pseudopetiole, auricles occasionally present

Morphology Reproductive morphology Inflorescences Synflorescence

Synflorescence paniculate, racemose or less commonly spicate formed by spikelets, each spikelet compound (1-) 2 basal glumes (sterile bracts) followed by 1- many anthecia (florets), each anthecium formed by an external lemma and an internal palea (sometimes absent) including one flower, less commonly barren

Morphology Reproductive morphology Flowers

Flower often bisexual with 2(-3) lodicules (scales), these rarely absent, (1-) 3 (-6-many) stamens and 2 (3) fused carpels, or less commonly unisexual-Fruit a caryopsis, sometimes modified with a fleshy pericarp .

Distribution

Throughout the Neotropics at all altitudes and in almost all vegetation types. See 'General Notes' for information on the distribution of the subfamilies. Native, though many genera have been introduced into cultivation or have become naturalized (See 'Number of genera').

Diagnostic

Key differences from similar families: Poaceae are sometimes confused with Cyperaceae, which differ from Poaceae in the following characters: Cyperaceae; leaves tristichous, with closed sheath, most of the genera without an adaxialligule; flowers with a perianth reduced to bristles or scales, sometimes absent, each flower protected by only one bract (glume), without forming one anthecium; fruit a nutlet. C3 and C4 photosynthesis. Silica bodies. Distinguishing characters (always present): Herbaceous (species from open habitats); herbaceous to lignified (from forest habitats). Culm with nodes and internodes; one leaf per node; leaves alternate. Adaxial ligule in the leaves (rarely absent). Flower included in two bracts (lemma and palea) that form the anthecium (or floret); one or more anthecia are grouped in spikelets that represent the basic inflorescence in grasses; two (rarely one) sterile bracts (glumes) at the base of the spikelet. Ovarysuperior, 2-(3)-carpellate, uniloculate.  Fruit a caryopsis.

Note

Number of genera: There is no citation of an exact number of genera and species of New World Poaceae.  The following estimates were published in the four volumes of the Catalogue of New World Grasses: Subfamilies Anomochlooideae, Bambusoideae, Ehrhartoideae, and Pharoideae - 72 genera (51 native) and 608 species (509 native) (Judziewicz et al., 2000). Subfamily Chloridoideae - 70 genera (62 native) and 672 species (604 native) (Peterson et al., 2001). Subfamily Pooideae - 121 genera (82 native) and 1526 species (1311 native) (Soreng et al., 2003). Subfamilies Panicoideae, Aristidoideae, Arundinoideae, and Danthonioideae - 119 genera (93 native) and 1613 species (1465 native) (Zuloaga et al., 2003). Genera of Poaceae ocurring in the Neotropics (* non native in the Neotropics, with adventitious or cultivated species) AnomochlooideaeAnomochloa Brongn.Streptochaeta Schrad. ex Nees AristidoideaeAristida L. ArundinoideaeArundo L.*Molinia Schrank.*Phragmites Adans. BambusoideaeActinocladum McClure ex Soderstr.Agnesia Zuloaga & Judz.Alvimia C.E.Calderón ex Soderstr. & LondoñoApoclada McClureArberella Soderstr. & C.E. CalderónArthrostylidium Rupr.Arundinaria Michx. Athroostachys Benth.Atractantha McClureAulonemia GoudotBambusa Schreb.*Cephalostachyum Munro*Chimonobambusa  Makin*Chusquea KunthColanthelia McClure & L.B.Sm.Cryptochloa SwallenDrendrocalamopsis (L.C. Chia & H.L. Fung) Keng f.*Dendrocalamus Nees*Drepanostachyum Keng f. *Diandrolyra StapfEkmanocloa Hitchc.Elytrostachys McClureEremitis DöllEremocaulon Soderstr. & LondoñoFargesia Franch. *Filgueirasia GualaFroesiochloa G.A. BlackGigantochloa Kurz ex Munro*Glaziophyton Franch.Guadua KunthIndocalamus Nakai*Lithachne P. Beauv.Maclurolyra C.E. Calderón & Soderstr.Melocanna Trin.*Merostachys Spreng.Mniochloa ChaseMyriocladus SwallenOchlandra Thwaites*Olmeca Soderstr.Olyra L.Otatea (McClure & E.W. Sm.) C. E. Calderón & Soderstr. *Pariana Aubl.Parodiolyra Soderstr. & ZuloagaPhyllostachys Siebold & Zucc.*Piresia SwallenPiresiella Judz., Zuloaga & MorronePleioblastus Nakai*Pseudosasa Makino ex Nakai*Raddia Bertol.Raddiella SwallenRehia FitjenReitzia SwallenRhipidocladum McClureSasa Makino & Shibata*Schizostachyum Nees*Semiarundinaria Makino ex Nakai*Sucrea Soderstr. ChloridoideaeAegopogon Humb. & Bonpl.Allolepis Soderstr.Bealia Scribn.Blepharidachne Hack.Blepharoneuron NashBouteloua Lag.Calamovilfa (A. Gray) Hack. ex Scribn. & Southw.Chaboissaea E. Fourn.Chladoraphis Franch.Chloris Sw.Cottea KunthCrypsis AitonCtenium Panz.Cynodon Rich.Dactyloctenium Willd.*Dasyochloa Willd. ex Rydb.Dinebra Jacq.*Distichlis Raf.Eleusine Gaertn.Enneapogon Desv. ex P. Beauv.*Enteropogon NeesEragrostis WolfErioneuron NashEustachys Desv.Fingerhuthia NeesGouinia E. Fourn. ex Benth.Gymnopogon P. Beauv.Hilaria KunthJouvea E. Fourn.Leptochloa P.Beauv.Leptothrium KunthLepturidium Hitchc. & EkmanLycurus KunthMicrochloa R. Br.  Monanthochloe Engelm.Muhlenbergia Schreb.Neesiochloa Pilg.Neobouteloua GouldNeostapfia Burtt DavyNeyraudia Hook. f.Orcuttia VaseyPappophorum Schreb.Pereilema J.PreslPleuraphis Torr.*Redfieldia VaseyReederochloa Soderstr. & H.F. DeckerRheochloa Filg. et al.Saugetia Hitchc. & ChaseSchaffnerella NashSchdonnardus Steud.Scleropogon Phil.Sohnsia Airy ShawSpartina Schreb.Sporobolus R. Br.Steirachne EkmanSwallenia Soderstr. & H.F. DeckerTetrachne Nees*Tragus Haller*Trichloris E. Fourn.Trchoneura AnderssonTridens Roem. & Schult.Triplasis P. Beauv.Tripogon Roem. & Schult.Triraphis R.Br.Tuctoria ReederUniola L.Vaseyochloa Hitchc.Willkommia Hack.Zoysia Willd. DanthonioideaeCortaderia StapfDanthonia DC.Hakonechloa Makino ex HondaLamphrothyrsus Pilg.Rytidosperma Steud.Schismus P. Beauv.*  Tribolium Desv.* EhrhartoideaeEhrharta Thunb.*     Leersia Sol. ex Sw.Luziola Juss.Oryza L.Rhynchoryza Baill.Streptogyna P. Beauv.Zizaniopsis Döll & Asch. PanicoideaeAchlaena Griseb.Acostia SwallenAcroceras StapfAgenium NeesAlloteropsis J. PreslAltoparadisium Filg. et al.  Amphicarpum KunthAndropogon L.Anthaenantia P. Beauv.Anthaenantiopsis Mez ex Pilg.Anthephora Schreb.Apluda L.Apochloa Zuloaga & MorroneArthraxon P. Beauv.Arthropogon NeesArundinella RaddiArundoclaytonia Davidse & R.P. EllisAxonopus P. Beauv.Bothriochloa KuntzeBrachiaria (Trin.) Griseb.*Calderonella Soderstr. & H.F. Decker Canastra Morrone et al.Cenchrus L.Centrochloa SwallenChaetium NeesChasmanthium LinkChrysopogon Trin.Coix L.*Cymbopogon Spreng.*Cyrtococcum Stapf*Cyphonanthus Zuloaga & MorroneDichanthelium (Hitchc. & Chase) GouldDichantium WillemetDigitaria HallerEchinochloa P. Beauv.Echinolaena Desv.Elionurus Humb. & Bonpl. ex Willd.Elymandra StapfEremochloa Büse*Eriochloa KunthEriochrysis P. Beauv.   Euclasta Franch*Gerritea Zuloaga, Morrone & KilleenGynerium Willd. ex P. Beauv.   Hemarthria R. Br.Heteropogon Pers.Homolepis ChaseHopia Zuloaga & MorroneHymenachne P. Beauv.Hyparrhenia Andersson ex E. Fourn.Hyperthelia ClaytonIchnanthus P. Beauv.Imperata CirilloIsachne R. Br.Ischaemum L.Ixophorus Schltdl. Karroochloa Conert & Türpe*Keratochlaena Morrone & ZuloagaLasiacis (Griseb.) Hitchc.Loudetia Hochst. ex Steud.Loudetiopsis ConertMegathyrsus (Pilg.) B.K. Simon & S.W.L. Jacobs*Melinis P. Beauv.*Mesosetum Steud.Microstegium Nees*Miscanthus AnderssonMnesithea KunthOcellochloa Zuloaga & MorroneOncorachis Morrone & ZuloagaOphiochloa Filg.,Davidse & ZuloagaOplismenopsis ParodiOplismenus P. Beauv.Orthoclada P. Beauv.Otachyrium NeesPanicum L.Paratheria Griseb.Parodiophyllochloa Zuloaga & MorronePaspalidium StapfPaspalum L.Pennisetum Rich.Phanopyrum (Raf.) NashPlagiantha RenvoizePogonatherum P. Beauv.*Pohlidium Davidse, Soderstr. & R.P. EllisPolytrias Hack.*Pseudechinolaena StapfReimarochloa Hitchc.Renvoizea Zuloaga & MorroneReynaudia KunthRhytachne Desv. ex Ham.Rottboellia L.f.*Rupichloa Salariato & MorroneSaccharum L.Sacciolepis NashSchizachyrium NeesScutachne Hitchc. & ChaseSetaria P. Beauv.Setariopsis Scribn.Sorghastrum NashSorghum Moench*Spheneria Kuhlm.Spodiopogon Trin.*Steinchisma Raf.Stenotaphrum Trin.Steyermarkochloa Davidse & R.P. EllisStreptostachys Desv.Tatianyx Zuloaga & Soderstr.Themeda Forssk.*Thrasyopsis ParodiThysanolaena NeesTrachypogon NeesTripsacum L.Triscenia Griseb.Tristachya NeesUrochloa P. Beauv.Zea L.Zeugites P. BrowneZuloagaea Bess. PharoideaePharus P. Browne PooideaeAgrostis L.Aira L.Amphibromus NeesAnthoxanthum L.*Arrhenatherum P. Beauv.Avena L.*Briza L. Bromus L. Calamagrostis Adans.Catapodium Link*Chascolytrum Desv.Dactylis L.*Deschampsia (L.) P. Beauv.Erianthecium ParodiFestuca L. Glyceria R. Br.Hainardia GreuterHolcus L.*Hordeum L. Lagurus L.Lolium L.*Melica L.Phalaris L.Phleum L.Piptochaetium J. PreslPoa L. Polypogon Desf.Rostraria Trin.Schedonorus P. Beauv.Secale L.*Stipa L.Trisetum Pers.Triticum L.*Vulpia C.C. Gmel. "Notes on the subfamilies and their distribution in the Neotropics Poaceae is presently divided into 12 subfamilies (Clark, 2009): Anomochlooideae, Pharoideae, Puelioideae, Bambusoideae, Erhartoideae, Pooideae, Danthonioideae, Arundinoideae, Micrairoideae, Aristidoideae, Chloridoideae and Panicoideae.  The first four subfamilies occur mainly in forests, frequently with pseudopetiolate leaves, and their photosynthetic pathway is C3 (Bambusoideae) or presumed C3 (GPWG, 2001).  The representatives of the other subfamilies occur predominantly in open savannas and grasslands and present generally linear and not pseudopetiolate leaves, with C3 or C4 photosynthesis, depending on the subfamily.  Of these subfamilies only Puelioideae is not represented in the Neotropics. Anomochlooideae is the most basal lineage in Poaceae, and includes two Neotropical genera: Anomochloa Brong., a monospecific genus with A. marantoidea Brong. endemic from the Atlantic Forest in the Southern Bahia, Brazil, and Streptochaeta Schrad., including about three neotropical forest species (Judziewicz et al., 2000). A. marantoidea Brong. is included in the Brazilian list of endangered species (MMA, 2008). The reproductive structures of these species are not considered as being true spikelets (GPWG, 2001). Aristidoideae includes three genera: Sartidia de Winter, with four African species and photosynthesis C3; Stipagrostis Nees, with ca. 50 African and Asian species and with C4 photosynthesis; and Aristida L., with ca. 250 species widespread in the tropics of the Old World and in the Neotropics. Until recently all the species of Aristida were mentioned as C4, with a double Kranz sheath around the vascular bundles, a unique characteristic among the Poaceae (Brown, 1977; Hattersley, 1986). However, recently Cerros-Talipa & Columbus (2009) found one C3 species, A. longifolia Trin., from Neotropical savannas and ""cerrados"". In the Neotropics there are about 130 species of Aristida (Zuloaga et al., 2003).Arundinoideae circumscription has changed very much in the taxonomic history of Poaceae. In its present circumscription it includes 33 to 38 species, all with photosynthesis C3 (GPWG, 2001). The tribe Arundineae, presently with a circumscription identical to the subfamily (GPWG, 2001), is cosmopolitan but best developed in southern latitudes (Clayton & Renvoize, 1986). In the Neotropics there are four genera, three of them introduced (Zuloaga et al., 2003)., and only Phragmites Adans., a cosmopolitan genus with three to four species (Clayton & Renvoize, 1986) includes a native member [P. australis (Nees) Döll].Bambusoideae representatives occur predominantly in forests, although some genera present species growing in open grasslands especially in high altitudes, e.g. the genus Chusquea Kunth, and are C3, as the three subfamilies mentioned above. Bambusoideae presents a very high richness, with ca. 1,400 species (Clark, 2009) and includes two traditional groups, the lignified bamboos (tribe Bambuseae), very diverse in the Neotropics, and the herbaceous bamboos (tribe Olyreae), almost restricted to this region, except by Olyra latifolia L., also occurring in Africa (native or introduced?) and Burgersiochloa Pilger, monospecific and endemic from New Guinea (Clayton & Renvoize, 1986). Bamboos are highly diverse in the Atlantic Rain Forest, Brazil, including four genera endemic from Olyreae (Oliveira et al., 2006) and only one from Bambuseae (Judziewicz et al., 2000). It is well represented in the Amazonian Forest as well, but more collections are needed in this area. Chloridoideae includes ca. 1,400 species (GPWG, 2001) from the paleotropics and Neotropics, mostly with C4 photosynthesis (only one African species of Eragrostis Wolf and one of Merxmuellera Conert known as C3, according to GPWG, 2001). These species occur mainly in open grasslands and savannas, and only a few species occur at the borders of forests. In the Neotropics there about 70 genera and 650 species (Peterson et al., 2001).Danthonioideae includes ca. 250 species, with C3 photosynthesis (GPWG, 2001), mainly from Australia, South Africa and New Zealand. It is represented in the New World by Cortaderia Stapf, Danthonia DC. and Rytidosperma Steud., including mainly extra-tropical species with a distribution similar to the Pooideae subfamily, and the introduced genera Schismus P. Beauv.  and  Tribolium Desv. (Zuloaga et al., 2003).Erhartoideae includes about 120 species (GPWG, 2001) from humid to flooded areas, widespread in the tropics and subtropics of the world, with C3 photosynthesis. In the Neotropics eight small genera are found, one of them introduced (Ehrharta Thunb.) and another extra-tropical (Zizania L., according to Judziewicz et al., 2000).Micrairoideae includes ca.170 species mainly from Australia and Asia, less common in the Neotropics, occurring in open savannas and grasslands and in the borders of forests, with C3 or C4 photosynthesis (Sanchez-Ken et al., 2007). It is represented in the Neotropics by the genus Isachne R. Br. (previously included in the Panicoideae subfamily) that includes ca. 100 species mostly from Tropical Asia (Clayton & Renvoize, 1986) and three to four species from the Neotropics. Panicoideae presents the highest richness of species within Poaceae, comprising ca. 3,270 species (GPWG, 2001) widespread in the tropics and subtropics, many C4, with three biochemical subtypes, according to Brown (1977) and Hattersley (1986), but also including several C3 species. These species belong especially to the tribe Paniceae, with most members in open areas and some groups from forests, and the tribe Andropogoneae, mainly from open areas. Paniceae from forests are often C3, but some species from open and arid areas are also C3 in this group, as in the ""campos rupestres"" of Southeastern Brazil, e.g. in Apochloa Zuloaga & Morrone and Renvoizea Zuloaga & Morrone (Sede et al., 2008). Likewise, Echinolaenainflexa (Poir.) Chase, a species typical of the ""cerrados"" in Central and Southeastern Brazil, is also C3. In the Neotropics there are ca. 120 genera (Zuloaga et al., 2003).Pharoideae is the next divergent lineage of Poaceae (GPWG, 2001), with true spikelets, these being unisexual and bearing only one staminate or one pistillate flower. This subfamily includes three genera and 12 species (GPWG, 2001) occurring both in the Neotropics and in the tropics of the Old World. The genus Pharus Browne is the only Neotropical genus, with ca. five forest species (Judziewicz et al., 2000).Pooideae includes ca. 3,300 species (GPWG, 2001), all C3, in open grasslands, occurring especially in extra-tropical areas. Soreng et al. (2003) indicated 121 genera in the New World, 82 native and 39 cultivated. Many members occur in the Andean Mountains. In Brazil, most species also occur in extra-tropical grasslands. Only a small number of these species extend to the Neotropical grasslands in the mountains of Southeastern Brazil."

Gramineae, E. Launert. Flora Zambesiaca 10:1. 1971

Morphology General Habit

Inflorescence usually terminal on the culms, rarely axillary, consisting of numerous spikelets arranged in spikes, or in racemes or in a panicle; the spikes or racemes either solitary or more often arranged along a common axis, sometimes digitate, often (Andropogoneae) subtended by a spatheole (sheath without lamina) and often branched, thus forming a complicated pseudo-panicle in which frequently a sessile spikelet is paired with a pedicelled one Mostly annual or perennial herbs, rarely shrubs or trees (Bambuseae), often with rhizomes, sometimes stoloniferous

Morphology Reproductive morphology Inflorescences

Spikelets (see pl. tab. 1) usually consisting of 2 (rarely more) glumes and 1 to several lemmas distichously arranged along a rhachilla; each lemma is opposed by a usually thinly membranous palea; enclosed between lemma and palea is the flower (the entire unit is termed a floret); glumes and/or lemmas often awned; florets, and sometimes the entire spikelet, with a basal indurated callus which is either blunt or acute; flower usually hermaphrodite, sometimes unisexual, rather small, consisting of 2-3 minute lodicules (representing the perianth) stamens and ovary; stamens hypogynous, usually 3, sometimes less, rarely 6 or more, with the 2-thecous anthers either opening lengthwise or with a terminal pore; ovary 1-locular; styles 2, rarely 1 or 3; stigmas usually plumose

Morphology Reproductive morphology Fruits

Fruit 1-seeded, usually a caryopsis, with the pericarp adnate to the seed or sometimes free (rarely fleshy)

Morphology General

Culms usually cylindrical, very seldom compressed, jointed with the nodes solid, the internodes hollow or sometimes solid, erect, ascending or prostrate, sometimes rooting at the nodes, branched or simple; branches at the base with a hyaline 2-keeled prophyll

Morphology Leaves

Leaves solitary, alternate in 2 ranks, all crowded around the base of the stem or/and spaced along the culm, in most cases consisting of sheath, ligule and lamina (tab. 1)

Morphology Leaves Leaf sheaths

Leaf-sheaths clasping the culm, usually rather tight, ribbed or smooth, with the margins free or connate to a varying degree and often overlapping, often with a pair of auricles on either side of the mouth

Morphology Leaves Ligules

Ligule situated transversely at the junction of sheath and lamina, adaxial, membranous or chartaceous, often reduced to a hairy rim, rarely completely absent in some genera

Morphology Leaves Leaf lamina

Leaf-laminae usually linear or linear-lanceolate, more rarely ovate or oblong, rather narrow, generally parallel-nerved but in a few instances tessellate, expanded, plicate, or sometimes rolled, thus appearing to be terete, often filiform, rarely amplexicaul or with a sagittate base, occasionally with the very base contracted into a pseudo-petiole, very rarely articulated with the sheath

Gramineae, W.D. Clayton. Flora of West Tropical Africa 3:2. 1972

Morphology General Habit

Annual or perennial herbs, rarely shrubs or trees, sometimes with rhizomes or stolons; stems erect, ascending or creeping, usually branched at the base, in perennials with sterile shoots and flowering stems (culms) mixed, in annuals only the latter present; culms cylindrical, rarely flattened, jointed, usually hollow in the internodes, closed at the nodes; branches subtended by a leaf, and with a 2-keeled hyaline leaflet (prophyll) at the base

Morphology Leaves

Leaves solitary at the nodes, sometimes crowded at the base of the stem, alternate and 2-rowed, consisting of sheath, ligule and blade; sheaths encircling the culm, with the margins free and overlapping or ± connate, frequently swollen at the base, the shoulders sometimes extended upwards into triangular auricles; ligule adaxial, placed at the junction of sheath and blade, membranous or reduced to a fringe of hairs, rarely absent (very rarely with a similar abaxial structure—the external ligule); blades usually long and narrow, rarely broad, flat or sometimes rolled or terete, parallel-nerved, rarely with transverse connections, usually passing gradually into the sheath, sometimes amplexicaul or with falcate auricles, rarely narrowed into a false petiole or articulated with the sheath

Morphology Reproductive morphology Inflorescences

Spikelets consisting of bracts distichously arranged along a slender axis (rhachilla); the two lower bracts (glumes) empty; the succeeding 1 to many bracts (lemmas) each enclosing a flower and opposed by a hyaline scale (palea), the whole (lemma, palea and flower) termed a floret; base of spikelet or floret sometimes with a horny prolongation downwards (callus); glumes or lemmas often bearing 1 or more stiff bristles (awns); this basic pattern of spikelet structure consistent throughout the family, though often much modified by reduction, suppression or elaboration of parts Inflorescence made up of spikelets arranged in a panicle, or in spikes or racemes, these either solitary, digitate, or disposed along a central axis; usually terminal, sometimes (especially in Andro-pogoneae) numerous, each inflorescence being subtended by a bladeless sheath (spatheole) and the whole flowering branch system condensed into a leafy false panicle

Morphology Reproductive morphology Flowers

Flowers usually bisexual, sometimes unisexual, small and inconspicuous; perianth represented by 2, rarely 3, minute hyaline or fleshy scales (lodicules); stamens hypogynous, 1–6, rarely more, usually 3, with delicate filaments and 2-thecous anthers opening by a longitudinal slit or rarely a terminal pore; ovary 1-locular, with 1 anatropous ovule often adnate to the adaxial side of the carpel; styles usually 2, rarely 1 or 3, generally with plumose stigmas

Morphology Reproductive morphology Fruits

Fruit mostly a caryopsis with thin pericarp adnate to the seed, rarely with free seed, still more rarely a nut or berry; caryopsis commonly combined with various parts of the spikelet, or less often the inflorescence, to form a false fruit; seed with starchy endosperm, an embryo at the base of the abaxial face, and a point or line (hilum) on the base or adaxial face marking the connection between pericarp and seed