Reseda L.
Reseda is an Old World genus of 55 species (Mabberley 2008). Most species are native from the Mediterranean area to Central Asia. Two species are native (or at least archaeophytic) in Belgium: Reseda lutea L. and R. luteola L. (Lambinon & al. 2004). Both these species are a source of yellow dyes and widely cultivated. A few species are also cultivated as ornamentals in Europe (Akeroyd & Knees 1995, Jäger & al. 2008).
1 Sepals and petals 4. Leaves always entire. Filaments persistent until fruit ripe (native) === Reseda luteola
Sepals and petals 5 or 6. Leaves pinnatifid to nearly entire. Filaments caducous or persistent === 2
2 Capsule pendulous. Seeds always rugose === 3
Capsule erect. Seeds smooth or tuberculate === 4
3 Sepals much enlarged at maturity (more than 5 mm long). Capsule 10-15(-20) mm long. Filaments distinctly dilated above the middle === Reseda phyteuma
Sepals not or only slightly enlarged at maturity (up to 5 mm long). Capsule 5-8 mm long. Filaments filiform, not dilated above the middle === R. odorata
4 Capsule 4 toothed. Stigmas 4. Petals white. Seeds tuberculate === R. alba
Capsule 3 toothed. Stigmas 3. Petals yellowish. Seeds smooth (native) === R. lutea
Additional alien: Reseda lutea L. subsp. vivantii (Monts.) Rovira (Spain, wool alien) (Verloove & Lambinon 2008). This record was erroneously ascribed to the Canarian endemic Reseda crystallina Webb et Berthelot by Lawalrée (1957). Reseda lanceolata Lag., a native of southeastern Spain and northwestern Africa, was recently recorded as an introduction with olive trees in a garden center (Hoste & al. 2009).
Literature:
Abdallah M.S. & de Wit H.C.D. (1978) The Resedaceae: a taxonomical revision of the family (finalinstalment). Mededelingen Landbouwhogeschool Wageningen 78-1. Landbouwhogeschool Wageningen, Netherlands: 416 p.
Akeroyd J.R. & Knees S.G. (1995) Reseda. In: Cullen J. & al. (eds.), The European Garden Flora, vol. 4. Cambridge University Press, Cambridge: 164-165.
Diez M.J. (1983) Estudio de las semillas de Resedaceae de Andalucia. Lagascalia 12: 109-115. [available online at: dialnet.unirioja.es/descarga/articulo/623961.pdf]
Hoste I., Verloove F., Nagels C., Andriessen L. & Lambinon J. (2009) De adventievenflora van in België ingevoerde mediterrane containerplanten. Dumortiera 97: 1-16.
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.
Lambinon J., Delvosalle L., Duvigneaud J. (avec coll. Geerinck D., Lebeau J., Schumacker R. & Vannerom H.) (2004) Nouvelle Flore de la Belgique, du Grand-Duché de Luxembourg, du Nord de la France et des Régions voisines (Ptéridophytes et Spermatophytes). Cinquième édition. Jardin botanique national de Belgique, Meise: CXXX + 1167 p.
Lawalrée A (1957) Reseda. In: Robyns W. (ed.), Flore Générale de Belgique, vol. 2, fasc. 3. Jardin Botanique de l’Etat, Bruxelles: 406-413.
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.
Valdés Bermejo E. (1993) Reseda. In: Castroviejo S. & al. (eds.), Flora Iberica, vol. 4. Real Jardín Botánico, Madrid: 440-475.
Verloove F. & Lambinon J. (2008) Neophytes in Belgium: corrections and adjustments. Syst. Geogr. Pl. 78: 63-79.
Yeo P.F. (1993) Reseda. In: Tutin T.G. & al. (eds.), Flora Europaea, vol. 1 (2nd ed.). Cambridge University Press, Cambridge: 418-420.