Phellodendron, or cork-tree, is a genus of deciduous, dioecious trees in the family Rutaceae, native to east and northeast Asia. It has leathery, pinnate leaves and yellow, clumped flowers. The name refers to the thick and corky bark of some (but not all) species in the genus. Fossil record Phellodendron seeds are known from the Early Oligocene of eastern North America, from the Mid Oligocene to the Pliocene of Europe and from the Pliocene of Asia and Japan. One fossil seed of Phellodendron has been extracted from bore hole samples of the Middle Miocene fresh water deposits in Nowy Sacz Basin, West Carpathians, Poland. Several Phellodendron macrofossils have been recovered from the late Zanclean stage of Pliocene sites in Pocapaglia, Italy. Cultivation and uses As an ornamental plant, Phellodendron is a tree for all seasons. In spring it has yellow flowers, in summer it provides foliage and shade, in fall the leaves turn bright yellow, and the textured bark and winding branches add interest in the winter. The female bears black drupes that attract birds and other wildlife through the late fall and winter. The cork-tree is resistant to drought and insects, and it can thrive in a variety of soils. It is hardy to zone 4 and it is easy to maintain, sometimes to the point of being invasive. One drawback is that the drupes fall and scatter, which may be undesirable on a formal lawn. The bark in some species is thick, resembling that of the cork oak, but is not thick enough for commercial cork production. It has been used to produce a yellow dye. One species, Phellodendron amurense (Chinese: 黄柏; pinyin: huáng bǎi; or 黄檗; pinyin: huáng bò; Russian: Бархат амурский "Barkhat Amurskiy" (Amur Velvet), also бархатное дерево, пробковое дерево), is one of the 50 fundamental herbs used in traditional Chinese medicine. Recently, Phellodendron has also attracted scientific attention because of the phytochemicals it produces: Berberine has antibacterial and anti-fungal properties Jatrorrhizine may be anti-mutagenic Phellodendrine has promise as an immune suppressant Palmatine may be a vasodilator The phytochemical descriptions are included for informational purposes only and not for treatment purposes. The research at this stage is very preliminary. Traditionally, the bark is the principal part of the plant used medicinally, although oil from the fruit is also used. The species grows in Northern China, and in the Khabarovsk and Primorskiy regions of Russia. Already identified