Luzula DC.
Luzula is a cosmopolitan genus with 108-115 species (Kirschner 2002, Mabberley 2008, Záveská & Vlček 2010). It is most diverse in temperate Eurasia and is represented in Belgium by six native species (Lambinon & Verloove 2012). All (incl. the very rare Luzula forsteri (Smith) DC.) have been reported as adventives outside their native Belgian distribution range, primarily near timber- or bark storages. Luzula luzuloides (Lam.) Dandy et Wilmott (syn.: L. albida (Hoffmann) DC., L. nemorosa (Pollich) E. Mey. non Hornem.) and L. sylvatica (Huds.) Gaudin (syn.: L. maxima (Reichard) DC.) are often cultivated for ornament and sometimes escape (incl. forms with variegated leaves) (see also Jäger & al. 2008).
Luzula is monophyletic but species relationships within the genus are difficult to determine (Záveská & Vlček 2010).
1 Most flowers borne singly (rarely some in pairs) (native) === Luzula pilosa and L. forsteri
Most flowers in clusters or heads of 3 or more === 2
2 Tepals white to stramineous === 3
Tepals brown (native) === L. campestris, L. multiflora and L. sylvatica
3 Capsule ca. ½ as long as tepals. Tepals 4,2-5,5 mm long, unequal === Luzula nivea
Capsule about as long as tepals. Tepals 2,3-3,2 mm long, subequal (native) === L. luzuloides
Literature:
Chrtek J. & Křísa B. (1980) Luzula. In: Tutin T.G. & al. (eds.), Flora Europaea, vol. 5. Cambridge University Press, Cambridge: 111-116.
Jäger E.J., Ebel F., Hanelt P. & Müller G. (eds.) (2008) Rothmaler Band 5. Exkursionsflora von Deutschland. Krautige Zier- und Nutzpflanzen. Springer Verlag, Berlin: 880 p.
Jäger E.J. & Werner K. (eds.) (2005) Rothmaler Band 4. Exkursionsflora von Deutschland. Gefässpflanzen: Kritischer Band. Springer Verlag, Berlin: 880 p.
Kirschner J. (2002) Species Plantarum. Flora of the world. Part 6. Juncaceae 1: Rostkovia to Luzula. Australian Biological Resources Study, Canberra: 1-237 [available online at: http://speciesplantarum.net/sites/alienplantsbelgium.bedefault/files/floras/j/juncaceae_1_1.pdf]
Lambinon J. & Verloove F. (avec coll. Delvosalle L., Toussaint B., Geerinck D., Hoste I., Van Rossum F., Cornier B., Schumacker R., Vanderpoorten A. & Vannerom H.) (2012) Nouvelle Flore de la Belgique, du Grand-Duché de Luxembourg, du Nord de la France et des Régions voisines (Ptéridophytes et Spermatophytes). Sixième édition. Jardin botanique national de Belgique, Meise: CXXXIX + 1195 p.
Mabberley D.J. (2008) Mabberley’s plant-book (3th ed.). Cambridge University Press, Cambridge: XVIII + 1021 p.
Stace C. (2010) New flora of the British Isles, 3th ed.: XXXII + 1232 p. Cambridge University Press.
Záveská D. & Vlček C. (2010) Molecular phylogeny of the genus Luzula DC. (Juncaceae, Monocotyledones) based on plastome and nuclear ribosomal regions: a case of incongruence, incomplete lineage sorting and hybridisation. Mol. Phylogenet. Evol. 57(2): 536-551.