Poa L.
  • Sp. Pl. 1: 67. 1753. (1 May 1753)

This taxon is accepted by Poaceae
Notes: More details could be found in The Plant List v.1.1. Originally in The Plant List v.1.0

General Description

34. Poa L.

Por R.W. Pohl y G. Davidse.

Perennes o anuales, cespitosas o rizomatosas. Tallos generalmente simples. Márgenes de las vainas libres; lígula una membrana; láminas lineares, el ápice cóncavo, navicular. Panícula terminal, generalmente con ramas verticiladas, al menos en el nudo más inferior. Espiguillas comprimidas lateralmente, con varios flósculos; desarticulación por encima de las glumas y entre los flósculos; glumas más cortas que las espiguillas, raramente casi de la misma longitud; flósculos generalmente bisexuales (Mesoamérica), raramente unisexuales; lemas lanceoladas a ovadas, carinadas, 5-nervias, no aristadas, las nervaduras marginales e intermedias de la quilla a menudo pelosas; callo frecuentemente lanoso con tricomas largos y crespos. Fruto una cariopsis; hilo linear. Aprox. 500 spp. Cosmopolita en regiones árticas y templadas, y en grandes altitudes en los trópicos.


Por Richard W. Pohl y Gerrit Davidse

Poa annua L., Sp. Pl. 68. 1753.

Anuales cespitosas; tallos 5–35 cm de largo, erectos y fasciculados, o decumbentes en sitios húmedos; plantas hermafroditas. Hojas glabras; márgenes de las vainas libres; lígula una membrana 1–4 mm de largo; láminas lineares, 5–11 cm de largo y 1–4 mm de ancho, aplanadas, el ápice cóncavo, navicular, las láminas basales blandas, patentes. Panícula terminal, 1.5–11 cm de largo y 1–5 cm de ancho, piramidal, abierta, ramas 1–2 en el nudo más inferior, patentes, desnudas en el 1/10–1/2 inferior; espiguillas 4–5.5 mm de largo, agrupadas, comprimidas lateralmente, con varios flósculos; desarticulación por encima de las glumas entre los flósculos; gluma inferior 1.5–2.7 mm de largo, 1-nervia, gluma superior 1.5–2.7 mm de largo, 3-nervia; flósculos 2–6, bisexuales; lemas 2.6–3.8 mm de largo, las nervaduras y el callo pilosos; páleas pilosas en las quillas. Fruto una cariopsis; hilo linear.

Rara, nebliselvas, zona norcentral; 800–1500 m; fl y fr may, oct; Guzmán 2073, Moreno 517; cosmopolita, presumiblemente introducida de Europa. Género con ca 500 especies, cosmopolita en regiones árticas y templadas, y en grandes altitudes en los trópicos.

Spikelets 2- to several-flowered, the rachilla disarticulating above the glumes and between the florets, the uppermost floret reduced or rudimentary; glumes acute, the first 1-nerved, the second usually 3-nerved; lemmas acute or subobtuse, 5-nerved, usually pubescent on the nerves, sometimes webbed at the base, the tip and margins often scarious.

Hierbas cespitosas a rizomatosas. Hojas con la vaina con los márgenes libres; lígula una membrana; láminalinear, el ápice navicular. Infl. terminal, una panícula. Espiguillas comprimidas lateralmente; desarticulaciónpor encima de las glumas y entre los flósculos; glumas más cortas que las espiguillas; flósculos varios, usual-mente bisexuales; lemas lanceoladas a ovadas, carinadas, 5-nervadas, no aristadas; páleas variadamente pubes-centes en las quillas.

Annuals or perennials. Culm bases infrequently swollen, or with bulbous sheath bases; new shoots intravaginal or extravaginal, rarely (in China) pseudointravaginal, intravaginal but with reduced or rudimentary lower leaf blades and weakly differentiated prophyl. Uppermost culm leaf sheath closed from 1/20th to entire length; ligule hyaline, membranous or infrequently papery; blade flat, folded, or involute, abaxially keeled, adaxially with 1 groove on either side of the midvein, apex prow-tipped. Inflorescence a terminal panicle; branches 1–9 per node; flowers all bisexual, or mixed bisexual and female (rarely male), with distal female flowers within spikelets, or with partially to wholly female spikelets or inflorescences. Spikelets laterally compressed, florets (1–)2–8(–10), rachilla disarticulating above glumes and between florets, uppermost floret vestigial; vivipary sometimes present; glumes mostly strongly keeled, unequal, or subequal, lower glume 1- or 3-veined, upper glume 3(or 5)-veined; lemmas laterally compressed, usually distinctly keeled, 5(–7)-veined, distal margins and apex membranous, apex awnless, rarely minutely mucronate; floret callus short, truncate, blunt, glabrous or webbed (with a dorsal tuft of woolly hairs), rarely with a line of hairs around base of lemma; palea subequal or infrequently to 2/3 as long as lemma, not gaping, keels green, distinctly separated, usually scabrid, smooth in Poa sect. Micrantherae, sometimes pilulose to villous, margins usually smooth, glabrous. Lodicules 2. Stamens 3, anthers sometimes vestigial. Ovary glabrous. Caryopsis oblong to fusiform, triangular to oval in cross section, sometimes grooved, free or adhering to the palea. 2n = 14–266. x = 7.

"Spikelets 2–several-fld, ± compressed laterally, disarticulating above the glumes and between the lemmas; glumes lanceolate to ovate, acute or subacute, 3-veined or the first 1-veined; lemma in most spp. keeled, often scarious at the margins and tip, generally 5-veined (but the intermediate veins obscure or obsolete in some spp.), often with a tuft of long, cobwebby hairs (called a web) at the base; uppermost florets reduced, unisexual or vestigial; rachilla in a few spp. finely puberulent or scaberulous, otherwise glabrous; lvs ending in a boat-shaped tip; panicles open or contracted, the branches generally in fascicles of 2–5, sometimes more. 150+, widespread, mostly temp. and boreal. Many of the spp. confluent through polyploid (often apomictic) forms."

Included Species

 Information From

MBG Floras Images
Flora images. Missouri Botanical Garden. Accessed on Jun. 2018.
  • A Missouri Botanical Garden
Flora de Nicaragua
WD Stevens, CU Ulloa, A Pool and OM Montiel. Missouri Botanical Garden Press, 2001
  • B Missouri Botanical Garden
Flora Of CHina @ efloras.org
'Flora of China @ eFloras (2008). Published on the Internet http://www.efloras.org/flora_page.aspx?flora_id=2 [accessed August 2016]' Missouri Botanical Garden, St. Louis, MO & Harvard University Herbaria, Cambridge, MA.
  • C Missouri Botanical Garden
New York Botanical Garden
Descriptions of plants should be attributed to the full citation for each individual article, chapter or book that is the source for each record, which should include the authors of original publication.
  • D Content licensed under Creative Commons Attribution-NonCommercial-ShareAlike 3.0 Unported License
Flora Mesoamericana
Gerrit Davidse, Mario Sousa Sánchez, A. O. Chater, Universidad Nacional Autónoma de México. Instituto de Biología, Missouri Botanical Garden, Natural History Museum (London, England) UNAM, 1994
  • E Missouri Botanical Garden
Flora de Panama
Robert E. Woodson, Jr. and Robert W. Schery Annals of the Missouri Botanical Garden Vol. 67, No. 4 (1980), pp. ii-xxxiii
  • F Missouri Botanical Garden
Manual de Plantas de Costa Rica
Hammel, B. E.; Grayum, M. H.; Herrera, C.; Zamora, N. Manual de Plantas de Costa Rica. Missouri Botanical Garden Press, 2003-2014
  • G Missouri Botanical Garden
  • H CC0 1.0 Universal (CC0 1.0).
World Flora Online consortium
World Flora Online Data. 2018.
  • I CC0 1.0 Universal (CC0 1.0).