Omphalodes Mill.
The generic limits of Omphalodes have long been very controversial (compare for instance Mill 2000, Mabberley 2008 and Weigend & al. 2013). Pollen morphology agrees with recent phylogenetic studies suggesting that Omphalodes probably is a polyphyletic group (Coutinho & al. 2012). Several species have recently been segregated (Otero & al. 2014) and all North American taxa are now in a separate genus Mimophytum Greenm. (Holstein & al. 2016). This new circumscription, however, does not affect the position of the taxa in this account since these are maintained in Omphalodes s.str. As traditionally accepted it counts ca. 30 Eurasian and Mexican species. Several are cultivated as ornamentals in Europe (see for instance Ingram 1960, Mill 2000, Jäger & al. 2008) but only few are more or less widespread in cultivation. Two species have been recorded as escapes in Belgium but only one (Omphalodes verna) in recent times.
Additional alien: Omphalodes linifolia (L.) Moench (SW-Eur., garden escape).
Literature:
Brand A. (1921) Borraginaceae – Borraginoideae – Cynoglosseae. In: Engler A. (ed.), Das Pflanzenreich 78 (IV/252). Engelmann, Leipzig: 236 p..
Coutinho A.P., Castro S., Carbajal R., Ortiz S. & Serrano M. (2012) Pollen morphology of the genus Omphalodes Mill. (Cynoglosseae, Boraginaceae). Grana 51(3): 194-205.
Edmondson J.R. (1977) Omphalodes. In: Materials for a Flora of Turkey, XXXIV. Notes Roy. Bot. Gard. Edinburgh 35: 300-302.
Ingram J. (1960) Studies in the cultivated Boraginaceae, 3. Omphalodes. Baileya 8: 137-141.
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.
Mabberley D.J. (2008) Mabberley’s plant-book (3th ed.). Cambridge University Press, Cambridge: XVIII + 1021 p.
Mill R.R. (2000) Omphalodes. In: Cullen J. & al. (eds.), The European Garden Flora, vol. 6. Cambridge University Press, Cambridge: 128-129.
Nesom G.L. (1988) Synopsis of the species of Omphalodes (Boraginaceae) native to the New World. Sida 13(1): 25-30.
Otero A., Jiménez-Mejías P., Valcárcel V. & Vargas P. (2014) Molecular phylogenetics and morphology support two new genera (Memoremea and Nihon) of Boraginaceae s.s. Phytotaxa 173(4): 241-277. [available online at: http://www.rjb.csic.es/especiesamenazadas/documentos/05_Otero_et_al_2014_Phytotaxa.pdf]
Van Ooststroom S.J. & Reichgelt Th.J. (1961) Boraginaceae. In: van Ooststroom S.J. & al. (eds.), Flora Neerlandica, vol. 4(1). KNBV, Amsterdam: 92-140.
Weigend M., Luebert F., Selvi F., Brokamp G. & Hilger H.H. (2013) Multiple origins for Hound’s tongues (Cynoglossum L.) and Navel seeds (Omphalodes Mill.) – The phylogeny of the borage family (Boraginaceae s.str.). Molecular Phylogenetics and Evolution 68: 604-618. [available online at: http://www.sci.sdsu.edu/plants/cryptantha/pdfs/Weigend_etal2013-Boraginaceae.pdf]