Miscanthus is a rather small genus with probably 20-25 species, almost exclusively confined to southeastern Asia (few extending into Africa).
The two taxa treated here (the only two in cultivation in Europe according to Walters & al. 1984, a view that is probably outdated now) are rather similar in general appearance and are obviously much confused in Belgium. However, they are easily distinguished on spikelet characters. Numerous cultivars with variegated leaves, coloured inflorescences or dwarf and giant forms recently arose in cultivation. However, several additional species are in cultivation elsewhere. Barkworth (2003) mentions five species as garden escapes for North America. Moreover, an additional taxon of Miscanthus, an allotriploid hybrid between M. sacchariflorus and M. sinensis (M. xgiganteus Greef et Deuter ex Hodkinson et Renvoize; according to Ibaragi & al. 2017 the correct name for this taxon is M. xlongiberbis (Hack.) Nakai f. ogiformis (Honda) Ibaragi) is increasingly cultivated as a source of biomass (Greef & Deuter 1993, Hodkinson & Renvoize 2001, Heaton & al. 2010) and might also occur as an escape (see for instance Brennenstuhl 2008). Since few years it is cultivated as a crop plant in Belgium as well (but not yet recorded as an escape; Bizot 2009). It seldom flowers and is not attractive as an ornamental. It is much reminiscent of Miscanthus sacchariflorus in general habit and spikelet characters but still has stouter rhizomes and wider leaves (often exceeding 30 mm) (see also Jäger & al. 2008). If inflorescences are produced lemma awns are short (4-5 mm) and geniculate (vs. absent or less than 5 mm and straight in M. sacchariflorus; Ibaragi & al. 2017). It might occur as a throw-out on rough ground in a near future. Another putative hybrid of these two species, M. xpurpurascens Andersson, is a diploid and probably also cultivated (it is often assigned to M. sinensis; e.g. Renvoize 2003). Its hybrid nature was proven by Jiang & al. (2013). According to Ibaragi & al. (2017), on the contrary, it is best assigned to M. sinensis var. sinensis, as f. purpurascens (Andersson) Nakai. It is distinguished by its purplish inflorescence.
Species of Miscanthus probably never produce viable seed in Belgium. At least, there is no evidence of self-sowing. All current populations originated from discarded rhizomes (garden waste).
- Spikelets unawned. Callus hairs 2-4 times as long as the spikelets. Plant with long creeping rhizomes === 1. Miscanthus sacchariflorus
- Spikelets awned, awn 6-12 mm long. Callus hairs less than twice as long as the spikelets. Plant more tufted, usually with shorter rhizomes === 2. M. sinensis
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