Bistorta affinis (D. Don) Greene (syn.: Polygonum affine D. Don, Persicaria affinis (D. Don) Ronse Decraene) (Himalayas) – Commonly grown for groundcover in Belgium but apparently rare as an escape from cultivation. Recorded, for instance, as an escape in Zonhoven in 1975 and more recently in a dry, sandy roadside in the port of Antwerpen in July 2012.
1. Gaillardia x grandiflora Van Houtte (= G. aristata Pursh x G. pulchella Foug.) (hort.) – A rare but locally naturalised escape from cultivation. The invasion history of Gaillardia x grandiflora in Belgium is rather well-documented. It was first collected in coastal dunes near St.-Idesbald in 1946 (close to residences and obviously escaping from nearby gardens).
Elaeagnus umbellata Thunb. (Himalayas, China, Japan) – A rather frequently planted ornamental, mainly in public gardens or parks. Sometimes introduced for revegetation purposes (on coalmine heaps or on sandraised sites) and readily escaping. The exact invasion history of Elaeagnus umbellata is poorly documented in Belgium. The first record dates back to 1953 when it was found as an escape on rough ground in Laken (Brussels). However, its more regular escape has only been recorded from the 1980’s onwards.
Guizotia is an African genus of at least six species (probably more according to recent phylogenetic research; see Geleta & al. 2010). One species, Guizotia abyssinica, is more or less widely cultivated as an oilseed crop, especially in the (sub-) tropics. However, experimental fields are also found in Belgium. Its seed (Niger seed) also is a major component in commercial birdseed mixtures.
Cota J. Gay
As currently circumscribed Iva comprises nine species, mostly native to temperate North America (Mabberley 2008). Recent molecular phylogenetic research supports the segregation of Cyclachaena Fresen. (with the noxious agricultural weed C. xanthiifolia (Nutt.) Fresen.; syn. Iva xanthiifolia Nutt.) from Iva (Karis 1995, Miao & al. 1995a, b).
Cyclachaena is a monospecific genus, native to North America. It was included for a long time in Iva but molecular phylogenetic research supports its separation from the latter (see for instance Karis 1995; Miao & al. 1995a,b; Mabberley 2008).
Picea A. Dietrich
Picea is a genus of about 35-40 species. Most are native in north temperate regions (primarily North America and Eurasia).