Hyacinthoides xmassartiana Geerinck (H. hispanica x H. non-scripta, H. xvariabilis P.D. Sell, nom.nud.?) (cult.) – A much increasing and widely naturalized garden escape, usually found in deciduous woodland, less frequently in hedgerows, road verges or on dumps. Most records of Hyacinthoides hispanica belong in fact to H. xmassartiana, the most frequently cultivated Hyacinthoides in Belgium nowadays.
Hyacinthoides xmassartiana arose in cultivation (artificial hybrid) but is at least partly fertile. However, at least part of the Belgian populations (for instance those of the coastal dunes near Adinkerke) probably resulted from a natural hybridization of native Hyacinthoides non-scripta and non-native H. hispanica. Backcrosses frequently occur and the boundaries between the taxa here involved might further blur (see also Kohn & al. 2009). As a rule however, Hyacinthoides xmassartiana is much more reminiscent of H. hispanica and rather unlikely to be confused with H. non-scripta. Hyacinthoides xmassartiana appears to be very competitive and tends to locally out-compete native H. non-scripta. It is much more vigorous, also as a result of bulbs being easily divided.
Selected literature:
Bleeker W., Schmitz U. & Ristow M. (2007) Interspecific hybridisation between alien and native plant species in Germany and its consequences for native biodiversity. Biological Conservation 137(2): 248-253.
Clement E.J. (2000) The hybrid bluebell, Hyacinthoides x massartiana. BSBI News 84: 24. [available online at: https://archive.bsbi.org.uk/BSBINews84.pdf]
De Blaay D.J.P. (2003) Hyacinthoides x massartiana Geerinck versus H. x variabilis Sell. Taxonomania 10: 12-13. [available online at: https://fr.scribd.com/document/16993078/TAXONOMANIA-10]
Duvigneaud J. & Saintenoy-Simon J. (2003) Au sujet de l'hybride entre Hyacinthoides non-scripta et Hyacinthoides hispanica. Adoxa 39: 20.
Geerinck D. (1997) Une épithète pour l’hybride Hyacinthoides hispanica (Mill.) Rothm. x H. non-scripta (L.) Chouard ex Rothm.: H. x massartiana Geerinck (Liliaceae). Belg. Journ. Bot. 129: 83-85.
Ietswaart J.H. (1983) Hybridization between Scilla non-scripta and S. hispanica (Liliaceae) in the Netherlands. Acta Bot. Neerl. 32: 467-480.
Kohn D.D., Hulme P.E., Hollingsworth P.M. & Butler A. (2009) Are native bluebells (Hyacinthoides non-scripta) at risk from alien congenerics? : Evidence from distributions and co-occurrence in Scotland. Biological Conservation 142: 61-74.
O’Rourke E. & Lysaght L. (2014) Risk Assessment of Hyacinthoides hispanica (including H. non-scripta x H. hispanica). [available online at: http://nonnativespecies.ie/wp-content/uploads/2014/03/Hyacinthoides-hisp...
Page K.W. (1987) Hybrid bluebells. B.S.B.I. News 46: 9. [available online at: https://archive.bsbi.org.uk/BSBINews46.pdf]
Quené-Boterenbrood A.J. (1984) Over het voorkomen van Scilla non-scripta (L.) Hoffmanns. & Link, S. hispanica Miller en hun hybride in Nederland. Gorteria 12: 91-104. [available online at: http://repository.naturalis.nl/document/567787]
Walravens E. & Geerinck D. (2007) Hyacinthoides x massartiana Geerinck (Liliaceae. Hyacinthaceae) signale pour la premiere fois en France? Taxonomania 20: 5. [available online at: https://fr.scribd.com/document/16993987/TAXONOMANIA-20]