Orlaya Hoffmann
Orlaya is a small genus of three species, originally native to southeastern Europe and Central Asia. One species, Orlaya grandiflora (L.) Hoffmann, is an archaeophytic weed of arable land in large parts of Europe, including Belgium (Lambinon & Verloove 2012). It has much decreased since the 1950s and might be nearly extinct now (e.g. Lambinon 1979, Fabri 1992). In the past years, it was repeatedly seen as grain alien in port areas in Antwerpen and Gent.
1 Rays 2-4(-5). Petals of marginal flowers ca. 5-8 mm long. Fruit 8-18 mm long === Orlaya daucoides
Rays 5-12. Petals of marginal flowers ca. 9-18 mm long. Fruit 6-8 mm long (native) === O. grandiflora
Literature:
Egorova T.V. & Vinogradova V.M. (2002) Taxonomic review of the genera Caucalis and Orlaya (Apiaceae) in the flora of the eastern Europe (in Russian). Bot. Zhurn. 87(11): 87-95.
Fabri R. (1992) Ombellifères indigènes, naturalisées ou adventices intéressantes pour la flore belge. Dumortiera 50: 4-15. [available online at: http://alienplantsbelgium.be/sites/alienplantsbelgium.be/files/dum50p4.pdf]
Heywood V.H. (1968) Orlaya. In: Tutin T.G. & al. (eds.), Flora Europaea, vol. 2. Cambridge University Press, Cambridge: 372-373.
Lambinon J. (1979) Quelques remarques à propos de la publication des commentaires à l’atlas de la Flore Belge et Luxembourgeoise. Nat. Mosana 32(2): 73-85.
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.
Lee B.-Y. & Downie S.R. (1999) A Molecular Phylogeny of Apiaceae Tribe Caucalideae and Related Taxa: Inferences Based on ITS Sequence Data. Syst. Bot. 24(3): 461-479. [available online at: http://www.life.illinois.edu/downie/Lee21999.pdf]
Lee B-Y., Levin G.A. & Downie S.R. (2001) Relationships within the spiny-fruited umbellifers (Scandiceae subtribes Daucinae and Torilidinae) as assessed by phylogenetic analysis of morphological characters. Systematic Botany 26(3): 622-642. [available online at: http://www.life.illinois.edu/downie/Levin2001.pdf]
Reduron J.P. (2007-2008) Ombellifères de France. Monographie des Ombellifères (Apiaceae) et plantes alliées, indigène, naturalisées, subspontanées, adventices et cultivées de la flore française. Tome 1-5. Bull. Soc. Bot. Centre-Ouest. N.S. Numéro spécial 26-30: 1-3004.