genera, and genera that have received particular emphasis include: Acer , Fagus , Carya , Forsythia , Taxodium , Pinus , Metasequoia , Lonicera , Magnolia , Malus , Quercus , Rhododendron , Syringa , Paulownia , Albizia , Ilex , Gleditsia and Tsuga . Other comprehensive collections include the Bradley