The high naturalistic value of the Botanical Garden is mostly due to the presence of monumental trees, among which the oriental plane trees (Platanus orientalis L.) (at the top), on the sides of the Eleven Fountain Staircase; the cork-oak (Quercus suber L.) (at the bottom) situated near the Orangery; the Turkish oak (Quercus cerris L.) near the herb garden; the downy oak (Quercus pubescens Willd.) located in the Mediterranean wood; and two Himalayan cedar trees (Cedrus deodara (Roxb. ex Lamb.) G.Don) near the Cavallerizza. In addition to these, there are 345 centuries-old specimens belonging to over 130 species, including Agathis robusta (C.Moore ex F.Muell.) F.M.Bailey, Ehretia acuminata R.Br., Erythrina crista-galli L., Nolina longifolia (Karw. ex Schult. & Shult.f.) Hemsl., Sequoia sempervirens (D.Don) Endl., Torreya grandis Fortune ex Lindl., Nannorrhops ritchieana (Griff.) Aitch., Cladrastis kentukea (Dum. Cours.) Rudd., Parrotia persica C.A. Mey., Apollonias barbujana (Cav.) Bornm, Fagus sylvatica L.