Phalaris L.

Phalaris – as here accepted – is a relatively small genus of 22 species, mostly concentrated in the temperate regions of the world (Europe, the Mediterranean area, northern Asia and the Americas). Its generic circumscription is somewhat unclear: species with unwinged glumes and long rhizomes (including native Phalaris arundinacea) are sometimes segregated as Phalaroides Wolf (syn.: Baldingera G. Gaertn. & al.). This taxonomic viewpoint was recently reinstalled by Valdés & Scholz (2006) for the Euro+Med Plantbase. However, recent molecular phylogenetic studies do not confirm this segregation (Voshell & al. 2011).

One species, Phalaris arundinacea is a common native species in Belgium. Several species are of economic importance, either as valuable hay or fodder, for erosion control, as ornamentals or as weeds of agricultural fields.

1 Perennial, strongly rhizomatous grasses === 2

1 Annual grasses === 3

2 Inflorescence not lobed, without obvious branches. Glumes distinctly winged. Sterile florets very unequal. Base of culm swollen (bulbous) === 1. Phalaris aquatica

2 Inflorescence lobed (branches obvious, at least basally). Glumes keeled but not winged. Sterile florets subequal. Base of culm not swollen === 2. P. arundinacea s.l. (incl. var. picta)

3 Wing of glumes with a very prominent tooth near apex. Spikelets deciduous in groups of 3-7, only one floret bisexual === 6. P. paradoxa

3 Wing of glumes without a prominent tooth near apex (at most minutely toothed or erose). Spikelets persistent, solitary, all florets bisexual === 4

4 Wing of glumes usually (at least in part) minutely toothed or erose. Sterile florets very unequal, one up to ½-1/3 of fertile floret length, the other vestigial or absent === 5. P. minor

4 Wing of glumes entire. Sterile florets subequal === 5

5 Sterile florets 1/5 of fertile floret length (or less) === 3. P. brachystachys

5 Sterile florets ca. ½ of fertile floret length === 4. P. canariensis

Additional aliens: Phalaris angusta Nees ex Trin. (syn.: P. chilensis J. Presl) (S-Am., wool alien), P. coerulescens Desf. (syn.: P. paradoxa var. coerulescens (Desf.) Paunero) (Medit., vector unknown) and P. platensis Henrard ex Heukels (S-Am., wool alien).



Anderson D.E. (1961) Taxonomy and distribution of the genus Phalaris. Iowa State Journ. Sci. 36: 1-96.

Auquier P. (1980) Graminées adventices nouvelles ou intéressantes pour la flore belge, II. Bull. Soc. Roy. Bot. Belg. 113: 3-13.

Baldini R.M. (1993) The genus Phalaris L. (Gramineae) in Italy. Webbia 47(1): 1-53.

Baldini R.M. (1995) Revision of the genus Phalaris L. (Gramineae). Webbia 49: 265-329.

Barkworth M.E. (2007) Phalaris. In: Barkworth M.E. & al. (eds.), Flora of North America north of Mexico, vol. 24: 764-773. Oxford University Press, New York-Oxford.

Clement E.J. (1982) Adventive news 22. BSBI News 30: 10-14.

Conert H.J. (ed.) (1998) Gustav Hegi Illustrierte Flora von Mitteleuropa. Band I, Teil 3 Poaceae (3.Auflage). Parey Buchverlag, Berlin: XXVII + 898 p.

Grenfell A.L. (1985) More on Phalaris paradoxa and related species. BSBI News 39: 8 (+ frontpage).

Jansen P. (1951) Flora Neerlandica, deel 1, aflevering 2. KNBV, Amsterdam: 272 p.

Jansen P. & Wachter W.H. (1915) Floristische aanteekeningen IX. Nederl. Kruidk. Arch. 1915: 142-171.

Jansen P. & Wachter W.H. (1916) Floristische aanteekeningen XI. Phalaris L. Nederl. Kruidk. Arch. 1916: 122-146.

Portal R. (2017) Le genre Phalaris à travers le monde. Vals près Le Puy: 106 p.

Stace C. (2010) New flora of the British Isles, 3th ed.: XXXII + 1232 p. Cambridge University Press.

Valdés B. & Scholz H. (2006) The Euro+Med treatment of Gramineae – a generic synopsis and some new names. Willdenowia 36: 657-669.

Voshell S.M., Baldini R.M. & Hilu K.W. (2015) Infrageneric treatment of Phalaris (Canary grasses, Poaceae) based on molecular phylogenetics and floret structure. Austr. Journ. Bot. 28(6): 355-367. [available online at:

Voshell S.M., Baldini R.M., Kumar R., Tatalovich N. & Hilu K.W. (2011) Canary grasses (Phalaris, Poaceae): molecular phylogenetics, polyploidy and floret evolution. Taxon 60(5): 1306-1316.

Taxonomic name: 
Scratchpads developed and conceived by (alphabetical): Ed Baker, Katherine Bouton Alice Heaton Dimitris Koureas, Laurence Livermore, Dave Roberts, Simon Rycroft, Ben Scott, Vince Smith