Abstract:
As a result of recent fieldwork in the island of Madeira (Portugal), 32 non-native vascular plant taxa: Aptenia ×vascosilvae, Calystegia silvatica, Cardamine occulta, Casuarina cunninghamiana and C. glauca, Convolvulus farinosus, Cotoneaster pannosus, Diplotaxis tenuifolia, Epilobium ciliatum, Erigeron floribundus, Euphorbia hypericifolia, E. maculata, E. serpens, Hedychium coronarium, Kalanchoe ×houghtonii, Lemna minuta, Lepidium oblongum, Malephora purpureocrocea, Metrosideros excelsa, Oenothera glazioviana, Oxalis dillenii, Phytolacca icosandra, Pistia stratiotes, Rumex palustris, Schinus terebinthifolia, Sisyrinchium micranthum (incl. S. rosulatum), Soliva sessilis, Sphagneticola trilobata, Tithonia diversifolia, Verbena incompta, V. litoralis and Youngia japonica, are reported as naturalized, xx of them for the first time. All these taxa are reportedly known as weeds or invasive, in climatologically comparable regions elsewhere in the world. In addition, records are provided for several taxa that are considered to be ephemerals at present, but for which a future naturalization is not unlikely. Finally, some miscellaneous notes are presented, on poorly known or recently reported aliens (for instance, the presence of Solanum chenopodioides is confirmed and in some habitats it even behaves as an invasive species). Identification keys for some species groups (Erigeron, Euphorbia subgenus Chamaesyce) are provided and many of the taxa are illustrated.
