|The "Great Katsura of Wachi", Torokawataira, Kami, Hyogo Prefecture, Japan|
Cercidiphyllum japonicum, known as the katsura (from its Japanese name カツラ, 桂), is a species of flowering tree in the family Cercidiphyllaceae native to China and Japan. It is sometimes called caramel tree for the light caramel smell it emits during leaf fall.
The shoots are dimorphic, with long shoots forming the structure of the branches and short shoots being born from their second year onward. The leaves are produced in opposite pairs on long shoots and singly on short shoots; they have a 1.4–4.7 cm petiole, and are rounded with a heart-shaped base and a crenate margin. Leaves on short shoots are larger, 3.7–9 cm long and 5–8.3 cm broad, and those on long shoots smaller, being 3.2–4.5 cm long and 1.9–3.2 cm broad. The leaves turn a variety of pinks and yellows in autumn and sometimes have a distinctive caramel scent when in fresh autumn colors. The flowers are inconspicuous and produced in early spring among the opening leaves, with male and female flowers on separate plants (dioecious). The fruit is a cluster of two to four follicles 1–1.8 cm long and 2–3 mm wide with each follicle containing several winged seeds.
The species is listed as endangered in China, but overall when Japanese populations are included C. japonicum is classified as being lower risk. The Chinese populations were sometimes distinguished in the past as Cercidiphyllum japonicum var. sinense Rehder & E.H.Wilson, but this is now generally regarded as not distinct from the species.
Katsura is a popular ornamental tree in Japan as well as elsewhere. In Japan, it is also grown for its timber, which is used for construction and woodworking.
Cercidiphyllum japonicum ‘Morioka Weeping’ Arnold Arboretum of Harvard University
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- Media related to Cercidiphyllum japonicum at Wikimedia Commons
- Cercidiphyllum japonicum images at the Arnold Arboretum of Harvard University Plant Image Database
- "Katsura, Cercidiphyllum japonicum, China 1910." Library Featured Images, Arnold Arboretum of Harvard University website, 14 September 2017. Accessed 1 May 2020.
- Friedman, William (Ned). "Leaves have teeth too." Posts from the Collection, Arnold Arboretum of Harvard University website, 18 April 2020. Accessed 1 May 2020.
- Dosmann, Michael and Andrew Gapinski. "Posts from the Field: Chasing Wilson in Northern Sichuan." Arnold Arboretum of Harvard University website, 16 October 2017. Accessed 1 May 2020.