1. Jacobaea maritima (L.) Pelser et Meijden (syn.: Senecio cineraria DC., S. gibbosus (Guss.) DC. subsp. cineraria (DC.) Peruzzi, N.G. Passal. et Soldano, Cineraria maritima L.) (W-and C-Medit.) – A very rare but increasing, locally naturalised escape from cultivation. First collected, without further details, in 1892 in Oostende. In the past decades more regularly recorded, for instance in Denderleeuw (1993), Kortrijk (2000; see Verloove 2001), Wavre (2002), Courcelles-Mandat (2005), Eine (2007), Gent (2008), Dendermonde (2008), etc. Jacobaea maritima is usually found in small number and is at most very locally more or less naturalised on old walls and quays. Records from rough ground, dumps,… are always ephemeral. So far, its has not yet been recorded on coastal (artificial) stony habitats in Belgium.
The exact identity of the plants in cultivation (and recorded as escapes) is controversial. These usually have leafy stems and woolly heads and certainly do not correspond with “Senecio cineraria s.str.” (the latter has most leaves in a basal rosette). They probably best match with Jacobaea ambigua (Biv.) Pelser et Veldkamp subsp. ambigua (syn.: Senecio ambiguus (Biv.) DC.) although they are not identical neither (see also Sell & Murrell 2006). Moreover, according to Conti & al. (2005) these taxa are better combined under Senecio gibbosus (Guss.) DC. (syn.: Jacobaea gibbosa (Guss.) B.Nord. et Greuter). The entire Jacobaea maritima-complex is badly in need of revision. Pending further research the Belgian populations are ascribed to Jacobaea maritima s.l.
Some populations are still different and more or less intermediate between Jacobaea maritima and J. vulgaris: stem and leaf indumentum is much less tomentose and achenes of tubular florets are hairy (as in J. vulgaris). These plants are fertile and represent hybrids (and backcrosses!) between these two species and are best referred to as Jacobaea xalbescens Verloove et Lambinon (Verloove & Lambinon 2011) (syn.: Senecio xalbescens Burbidge et Colgan). Such plants were recently recorded in Gent and are possibly more widespread wherever both parents occur sympatrically (see also Murphy 1981, Hebbel 2015-2016). In the British Isles, a hybrid with Jacobaea erucifolia has also been recorded (Burton 1979).
Selected literature:
Burton R.M. (1979) Senecio cineraria DC. x S. erucifolius L. in E. Kent. Watsonia 12: 333-334.
Conti F., Abbate G., Alessandrini A. & Blasi C. (eds.) (2005) An annotated checklist of the Italian vascular flora. Palombi Editori, Roma: 420 p.
Hebbel J. (2015-2016) Ein Fund der Kreuzkraut-Hybride Jacobaea x albescens (Senecio x albescens) in Schleswig-Holstein. Kiel. Not. Pflanzenkd. 41: 58-65. [available online at: http://ag-geobotanik.de/Kieler_Notizen/KN41_15_16/08%20Senecio%20Hebbel....
Livermore P. & Livermore L. (1992) Senecio x albescens (S. cineraria x S. jacobaea.) BSBI News 61: 12.
Mabberley D.J. (1983) The dusty miller's tale or Senecio cineraria DC. restored. Watsonia 14(3): 279-280.
Murphy J.P. (1981) Senecio x albescens Burbidge & Colgan at Killiney, Co. Dublin: a seventy-eight years old population. Watsonia 13: 303-311.
Sell P. & Murrell G. (2006) Flora of Great Britain and Ireland. Vol. 4 Campanulaceae – Asteraceae. Cambridge University Press, Cambridge: XXVIII + 624 p.
Verloove F. (2001) Conyza bilbaoana J. Rémy, Cotoneaster x watereri Exell en Erigeron karvinskianus DC., nieuw voor de Belgische flora in Kortrijk. Dumortiera 78: 24-27.
Verloove F. & Lambinon J. (2011) The non-native vascular flora of Belgium: new combinations and a new variety. New Journ. Bot. 1(1): 38-42.