Ammi L.
Ammi is, in its traditional circumscription, a genus of 3-4 species native to the Mediterranean area, western Asia and Macaronesia (Mabberley 2008). The two species treated in this account are rather weedy and have spread far beyond their original distribution range. Both are also increasingly grown as cut-flowers (e.g. van der Meijden 2005) and are used medicinally which might also explain part of their recent occurrences.
The exact placement of Ammi visnaga remains uncertain. Some recent research seems to support the transfer of this species to a separate genus Visnaga Mill. (as V. daucoides) (e.g. Reduron 2007-2008). Molecular data rather suggest a close relationship to the morphologically very different genus Smyrniopsis Boiss. (Downie & al. 2010). Pending further studies it is here maintained in its traditional sense (which is in accordance with e.g. Euro+Med Plantbase).
1 Rays remaining slender at maturity. Lower leaves usually with elliptical or obovate, serrate lobes (much wider than the lobes of the upper leaves) === Ammi majus
Rays becoming rigid, thick and incurved at maturity. Lower leaves with linear to filiform, entire lobes (not notably different than the lobes of the upper leaves) === A. visnaga
Literature:
Downie S.R., Spalik K., Katz-Downie D.S. & Reduron J.-P. (2010) Major clades within Apiaceae subfamily Apioideae as inferred by phylogenetic analysis of nrDNA ITS sequences. Plant Div. Evol. 128: 111-136. [available online at: http://www.life.illinois.edu/downie/DownieITS.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.
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.
Tutin T.G. (1968) Ammi. In: Tutin T.G. & al. (eds.), Flora Europaea, vol. 2. Cambridge University Press, Cambridge: 353.
Van der Meijden R. (2005) Heukels’ Flora van Nederland (23e druk). Wolters-Noordhoff, Groningen: 685 p.