Morphology and pollen fertility of native and non-native bluebells in Great Britain

摘要

Background There is considerable concern that the native British bluebellHyacinthoides non-scripta(Asparagaceae) is at risk due to hybridisation with naturalised British non-native bluebells. However, the taxonomic identity of British non-natives is uncertain, and they are either referred to as Spanish bluebells,H.hispanica, or as hybrids betweenH.non-scriptaandH.hispanica. Aims To establish whether a detailed morphological analysis can shed light on the taxonomic identity of non-native British bluebells. Methods We measured 28 morphological characters and recorded the pollen fertility of native and non-native bluebells in Britain and compared these withH.hispanicapopulations from Portugal. Results British non-native bluebells appeared morphologically close toH.hispanicabut occupied a separate phenotypic space. All three taxa showed high morphological variability with overlapping ranges, however, at least 92.8% of trait means were significantly different between any pair-wise taxon comparison. Sixty per cent of continuous traits were significantly larger in British non-native bluebells compared toH.non-scriptaandH.hispanica. In contrast, pollen fertility was significantly lower in British non-natives (79%) compared toH.non-scripta(94%) andH.hispanica(84%). Conclusions These results are consistent with, however, do not provide conclusive evidence for, the possible hybrid status of British non-native bluebells.