Regent, Royal and Carlton Terrace Gardens lasted until 2011, when it was felled due to disease. The following tree species were recorded in the gardens at the end of the 20th century: ash ("Fraxinus excelsior"), beech, black poplar ("Populus nigra"), cherry ("Prunus avium"), common lime ("Tilia × europaea"), English elm ("Ulmus minor" 'Atinia'), hawthorn ("Crataegus monogyna"), holly, horse chestnut ("Aesculus hippocastanum"), laburnum ("Laburnum anagyroides"), Norway maple ("Acer platanoides"), oak ("Quercus robur"), rowan ("Sorbus aucuparia"), silver birch ("Betula pendula"), small leafed lime ("Tilia cordata"), sweet chestnut ("Castanea sativa"), sycamore ("Acer pseudoplatanus"), tulip tree ("Liriodendron tulipifera"), whitebeam ("Sorbus aria"), white poplar ("Populus alba"), and wych elm ("Ulmus glabra").
Sorbus torminalis the bark on old trees. The species has sometimes been placed in its own genus, "Torminalis". Recent molecular phylogenetics confirms an earlier taxonomic opinion that the genus "Sorbus" as defined in the broad sense is not monophyletic, but the simple-leafed species traditionally included in "Sorbus" are a monophyletic group; this species would be included in a clade called "Aria" (genus "Aria" or "Sorbus" subgenus "Aria") as the species "Aria torminalis" Beck. It is a sexually reproducing diploid species that forms diploid and polyploid hybrids with members of subgenus "Aria" (whitebeams). A number of often very localised stable apomictic polyploid species