Spring bluegrass

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Spring bluegrass
A – E Poa annua L. A Habitus B Inflorescence C glumes D Single flower with palea and anthers E Single flowers F – H Poa infirma Kunth F Habitus G Spikelets H Single flower with palea and anthers Drawings by Soreng (2007).

A-E Poa annua L. A habitus B inflorescence C glumes D single flower with palea and anthers E individual flowers F-H Poa infirma Kunth F habit G spikelets H single flower with palea and anthers drawings of Soreng (2007).

Systematics
Commelinids
Order : Sweet grass (Poales)
Family : Sweet grasses (Poaceae)
Subfamily : Pooideae
Genre : Bluegrass ( Poa )
Type : Spring bluegrass
Scientific name
Poa infirma
Kunth

Spring bluegrass ( Poa infirma ) is a species of grass belonging to the genus of bluegrass (Poa). The species is native to the Mediterranean region and Western Europe, from there it was introduced and naturalized in many regions, such as North and South America, Australia and New Zealand. It occurs only rarely and inconsistently in Central Europe.

features

The spring bluegrass is an annual grass species that forms loose, low clumps with a narrow base. The stature height of the ascending to upright, often kneeled stalks is 2 to 18 or 5 to 25 centimeters or 1 to 25 centimeters. The delicate and soft stalks of the pale green grass are predominantly fertile. The culms are smooth, rounded or flattened, the leaves with a leaf sheath closed to about a third of their length , the ligule 0.5 to 3 millimeters long, blunt at the apex. The leaf blades are spread out or folded lengthways, 1 to 7 or 2 to 8 centimeters long and about 1 to 3 millimeters wide with a boat-shaped tip.

The open panicle is about 1 to 6 centimeters long in North America and 2 to 10 centimeters in China, with an elongated egg-shaped to rhombic outline, always longer than it is wide. At the lowest node there are one to three (to five) panicle branches that are straight and ascending (not horizontally spread), the longest branches with 5 to 9 (10) moderately crowded spikelets . The spikelets are 3 to 4 (5) millimeters long (in Europe usually smaller) and lanceolate, with (3 or 4) 5 to 6 flowers, the outer (distal) of which are often purely female, the flowers on the axis slightly apart to slightly overlapping. Their glumes are unequal and keeled, the lower one, the upper three-veined. The lemmas reach 2 to 2.5 millimeters in length, they are lanceolate and keeled with densely hairy nerves.

From the closely related and very similar annual panicle Poa annua , the spring panicle is best distinguishable by its smaller spikelets and the erect, never flat, lower panicle branches.

The flowering time for Spain is October to May, in China May to August. In England it blooms all year round.

distribution

The spring bluegrass was first described using material from the Andes, near Bogotá in Colombia , at about 1,360 meters above sea level, but it is actually a species introduced on the American continent and originates from Europe. Spring bluegrass occurs in western and southern Europe (Mediterranean-Atlantic distribution), in the west north to the south of England (where it is assessed as indigenous. There is only one single finding from Ireland in 1987 in a garden). In the south, the distribution reaches North Africa. The eastern limit of the distribution is unclear. The occurrences in Iran, India (in the Himalayas) and China are also assessed as indigenous

Finds from North America are mainly from the west, north to British Columbia , California, Georgia and Oregon to Baja California in Mexico. In South America it occurs in the west, south to Argentina and Chile. Other imported occurrences are in Australia and New Zealand.

Spring bluegrass rarely occurs as an advent in Central Europe . In Austria, the species has been identified several times in Vienna. Evidence for the German and Swiss flora is missing so far.

The species grows in cultivated land, often in shaded places with open, disturbed vegetation cover, for example along beaten paths. It prefers sandy locations.

genetics

The similar, much more widespread species annual bluegrass ( Poa annua ) is an allo tetraploid species that emerged from the diploid species spring bluegrass ( Poa infirma ) and lager bluegrass ( Poa supina ). This was first postulated on the basis of genetic experiments by Thomas Gaskell Tutin from 1957 and, after doubts that have arisen in the meantime, clearly confirmed by modern studies of the nuclear and plastid genome.

Web links

Commons : Spring bluegrass ( Poa infirma )  - Collection of images, videos and audio files

Individual evidence

  1. ↑ a b c d Robert J. Soreng & Paul M. Peterson (2012): Revision of Poa L. (Poaceae, Pooideae, Poeae, Poinae) in Mexico: new records, re-evaluation of P. ruprechtii, and two new species , P. palmeri and P. wendtii. PhytoKeys 15: 1-104. doi: 10.3897 / phytokeys.15.3084
  2. ↑ a b c d e Poa infirma Kunth in Humboldt et al. , Flora of China online, Vol. 22 (Poaceae). online at www.efloras.org
  3. ↑ a b Poa infirma. Ecological Flora of the British Isles , ecoflora.org.uk/
  4. ^ A b Ana Ortega-Olivencia & Juan A. Devesa (2018): Updated checklist of Poa in the Iberian Peninsula and Balearic Islands. PhytoKeys 103: 27-60. doi: 10.3897 / phytokeys.103.26029
  5. ↑ a b Dinesh Chandra Nautiyal & RD Gaur (2017): Poa L. species in Uttarakhand, India and keys for their identification. Taiwania 62 (1): 75-92.
  6. ↑ a b Mahsa Kavousi, Mostafa Assadi, Taher Nejadsattari (2015): Taxonomic revision of the genus Poa L. in Iran, new additions to Flora Iranica, and a new identification key. Turkish Journal of Botany 39: 105-127. doi: 10.3906 / bot-1311-31
  7. ↑ a b A.R. Clapham, EF Warburg, TG Tutin: Flora of the British Isles. Cambridge University Press, 2nd edition 1962. Poa infirma at p. 1138.
  8. ^ Grass Manual Treatment
  9. ↑ Poa infirma. Online Atlas of the British and Irish Flora
  10. ^ Poa infirma Kunth , distribution map . GBIF Global Biodiversity Information Facility, accessed July 22, 2020.
  11. ^ Rolf Diran (2016): Contributions to the adventurous flora of Vienna and Lower Austria. Neilreichia 8: 27-39.
  12. ^ Thomas Gaskell Tutin : A contribution to the experimental taxonomy of Poa annua L. In: Watsonia , Volume 4, 1957, pp. 1-10.
  13. ↑ Nikolai N. Nosov, Valery N. Tikhomirov, Eduard M. Machs, Alexander V. Rodionov (2019): On polyphyly of the former section Ochlopoa and the hybridogenic section Acroleucae (Poa, Poaceae): insights from molecular phylogenetic analyzes. Nordic Journal of Botany 2019: e02015. doi: 10.1111 / njb.02015
  14. ↑ Qing Mao & David R. Huff (2012): The Evolutionary Origin of Poa annua L. Crop Science 52 (4): 1910-1922. doi: 10.2135 / cropsci2012.01.0016