Belongs within: Poales.
Contains: Bambusoideae, Pooideae, Ehrhartoideae, Aristidoideae, Panicoideae, Arundinoideae, Micrairoideae, Danthonioideae, Chloridoideae.
The Poaceae are the grasses, a distinctive group of monocotyledons that are one of the most significant plant groups alive today. It is estimated that grass-dominated landscapes make up about one-fifth of the terrestrial surface of the planet. Grasses also contribute to a significant portion of the human diet, either directly (being grown for grain) or indirectly (as fodder for livestock). Members of the Poaceae share a unique fruit form, the caryopsis, in which the outer integument is developmentally fused to the inner wall of the ovary. The leaf epidermis contains a mixture of long and short cells with short cells containing silica bodies (phytoliths; Grass Phylogeny Working Group 2001). A number of derived subgroups have evolved the C4 photosynthetic pathway in which Rubisco is restricted to the bundle sheath veins surrounding the veins (Grass Phylogeny Working Group 2001). The earliest unequivocal grass fossils are known from the Palaeocene (Collinson et al. 1993).
Members of the basal clades Anomochlooideae, Pharoideae and Puelioideae are relatively broad-leaved herbs found growing on shaded tropical forest floors. These three clades together account for only about thirty species; the great majority of grass species belong to a clade united by having at most two lodicules (small scales below the ovary) in the flower, as well as by molecular data. The Neotropical Anomochlooideae bear flowers whose component parts are of uncertain homology with those of the true grass spikelet, which therefore appears to represent a synapomorphy of a clade of all grasses excluding Anomochlooideae. Anomochloa marantoidea has basal leaves with long pseudopetioles whereas Streptochaeta has leaves borne along the culm (Kellogg 2015).
The pantropical Pharoideae bear resupinate leaves with oblique lateral veins running straight from the mid-nerve to the margins. Lemma margins are usually free in species of Pharus whereas they are fused in Scrotochloa and Leptaspis (Kellogg 2015). The Puelioideae are tropical African grasses bearing multi-flowered spikelets with female-sterile proximal florets (Grass Phylogeny Working Group 2001). Streptogyna is a small genus found in the Americas and Africa with secund spikelets disarticulating between the florets.
Systematics of Poaceae
Characters (Grass Phylogeny Working Group 2001): Inflorescence highly bracteate. Perianth reduced or lacking. Pollen with single opening, lacking scrobiculi, but with intraexinous channels. Seed coat fused to inner ovary wall at maturity, forming a caryopsis. Embryo lateral in position, highly differentiated with obvious leaves, shoot and root meristems.
<==Poaceae (see below for synonymy)
|--Anomochlooideae [Streptochaetoideae]GPWG01
| |--Anomochloa Brongniart 1851 [Anomochloeae]K15
| | `--A. marantoideaGPWG01
| `--Streptochaeta Nees 1829 [Streptochaeteae]K15
| |--S. angustifoliaGPWG01
| |--S. sodiroanaGPWG01
| `--S. spicataGPWG01
`--+--Pharoideae [Leptaspidoideae, Phareae]GPWG01
| |--Scrotochloa Judziewicz 1984K15
| |--Leptaspis Br. 1810K15
| | `--L. banksiiB00 [=Pharus banksiiB78]
| `--Pharus Browne 1756GPWG01, KC01
| |--P. glaber [incl. P. brasiliensis]S06
| |--P. lappulaceusGPWG01
| |--P. latifoliusGPWG01
| `--P. meziiGPWG01
`--+--PuelioideaeGPWG01
| |--Guaduella Franch. 1887 [Guaduelleae]K15
| | |--G. marantifoliaGPWG01
| | `--G. oblongaK15
| `--Puelia Franch. 1887 [Puelieae]K15
| |--P. ciliataGPWG01
| `--P. schumannianaGPWG01
`--+--+--+--BambusoideaeK15
| | `--PooideaeK15
| `--+--EhrhartoideaeK15
| `--Streptogyna Beauv. 1812 [Streptogyneae]K15
| |--S. americanaGPWG01
| `--S. crinitaK15
`--+--AristidoideaeK15
`--+--PanicoideaeK15
`--+--+--ArundinoideaeK15
| `--MicrairoideaeK15
`--+--DanthonioideaeK15
`--ChloridoideaeK15
Poaceae incertae sedis:
CutandraYY22
HomopogonYY22
KerinozomaYY22
SchaffneraYY22
AtractocarpaYY22
FournieraYY22
CinnagrostisYY22
Psilurus incurvus (Gouan) Schinz & Thellung 1913PL04
Paniculum agrostidesSF98
LophochloaPL04
|--L. cristata (Linnaeus) Hyl. 1953PL04
`--L. pumillaK90
SteymarkochloaGPWG01
Monoporites annulatus Pares Regali et al. 1974CBH93
Elyonurus royleanusPP07
Gadua paniculataHSS13
Filifolium sibiricumRJ11
Bleparidachne kingiiH93
Yorkia gramineoides Ward 1900CBH93
Graminidites Harris 1965CBH93
Trichachne californicaHW96
Desmazieria Dumort. 1822KC01
Krombholzia Rupr. ex Fourn. 1876KC01
Penicillaria Willd. 1809KC01
Puccinella Parl. 1848 (nom. cons.)KC01
Heterochloe alpinaH44
GraminophyllumP92
Streptachne stipoidesB78
Programinis laminatusK15
BerriochloaK15
Sitanion hordeoidesM68
Poaceae [Astreptae, Avenaceae, Festucaceae, Gramineae, Hordeaceae, Milieae, Panicaceae, Poineae, Stipaceae, Streptatherae, Tristegineae]
*Type species of generic name indicated
References
[B78] Bentham, G. 1878. Flora Australiensis: A description of the plants of the Australian Territory vol. 7. Roxburghiaceae to Filices. L. Reeve & Co.: London.
[B00] Braby, M. F. 2000. Butterflies of Australia: their identification, biology and distribution vol. 2. CSIRO Publishing: Collingwood (Victoria).
[CBH93] Collinson, M. E., M. C. Boulter & P. L. Holmes. 1993. Magnoliophyta (‘Angiospermae’). In: Benton, M. J. (ed.) The Fossil Record 2 pp. 809–841. Chapman & Hall: London.
[GPWG01] Grass Phylogeny Working Group. 2001. Phylogeny and subfamilial classification of the grasses (Poaceae). Annals of the Missouri Botanical Garden 88 (3): 373–457.
[H44] Hammer, M. 1944. Studies on the oribatids and collemboles of Greenland. Meddelelser om Grønland 141 (3): 1–210.
[H93] Hickman, J. C. (ed.) 1993. The Jepson Manual: Higher Plants of California. University of California Press: Berkeley (California).
[HW96] Hicks, A. L., & R. F. Whitcomb. 1996. Diversity of the leafhopper (Homoptera: Cicadellidae) fauna of northern Chihuahuan grasslands, with emphasis on gypsum grasslands and description of a new species of Athysanella (Cicadellidae: Deltocephalinae). Proceedings of the Entomological Society of Washington 98 (1): 145–157.
[HSS13] Hirschfeld, E., A. Swash & R. Still. 2013. The World’s Rarest Birds. Princeton University Press: Princeton (New Jersey).
[K90] Keighery, G. J. 1990. Vegetation and flora of Shark Bay, Western Australia. In: Berry, P. F., S. D. Bradshaw & B. R. Wilson (eds) Research in Shark Bay: Report of the France-Australe Bicentenary Expedition Committee pp. 61–87. Western Australian Museum.
[K15] Kellogg, E. A. 2015. The Families and Genera of Vascular Plants vol. 13. Flowering Plants: Monocots: Poaceae. Springer.
[KC01] Kirk, P. M., P. F. Cannon, J. C. David & J. A. Stalpers. 2001. Ainsworth & Bisby’s Dictionary of the Fungi 9th ed. CAB International: Wallingford (UK).
[M68] Munz, P. A. 1968. Supplement to a California Flora. University of California Press.
[PP07] Pandey, R. P., & P. M. Padhye. 2007. Studies on phytodiversity of Arid Machia Safari Park-Kailana in Jodhpur (Rajasthan). Bulletin of the Botanical Survey of India 49: 15–78.
[PL04] Pohl, G., & I. Lenski. 2004. Zur Verbreitung und Vergesellschaftung von Pennisetum orientale Rich. in Nordeuböa (Griechenland) (Poaceae, Paniceae). Senckenbergiana Biologica 83 (2): 209–223.
[P92] Poinar, G. O., Jr. 1992. Life in Amber. Stanford University Press: Stanford.
[RJ11] Rising, J. D., A. Jaramillo, J. L. Copete, P. G. Ryan & S. C. Madge. 2011. Family Emberizidae (buntings and New World sparrows). In: Hoyo, J. del, A. Elliott & D. A. Christie (eds) Handbook of the Birds of the World vol. 16. Tanagers to New World Blackbirds pp. 428–683. Lynx Edicions: Barcelona.
[SF98] Saikkonen, K., S. H. Faeth, M. Helander & T. J. Sullivan. 1998. Fungal endophytes: a continuum of interactions with host plants. Annual Review of Ecology and Systematics 29: 319–343.
[S06] Stuckert, T. 1906. Segunda contribución al conocimiento de las gramináceas Argentinas. Anales del Museo Nacional de Buenos Aires, serie 3, 6: 409–555.
[YY22] Yampolsky, C., & H. Yampolsky. 1922. Distribution of sex forms in the phanerogamic flora. Bibliotheca Genetica 3: 1–62.