PlantaeDB Logo
Login Sign-up

Genus Cercidiphyllum in Family Cercidiphyllaceae

In botanical taxonomy, a genus (plural genera) is a rank used to group closely related species within a family. In the hierarchy, genus sits below family and above species.

Genera are defined by shared morphological, anatomical, and genetic characteristics (for example, features of flowers, fruits, seeds, or leaves) that indicate a close evolutionary relationship among the species they contain.

Each genus can include one or more species. Examples include Rosa (roses) and Solanum (nightshades, including tomato and eggplant).

Do you wish to read more about plant taxonomy? Click here!

Genus Description

Suggest a correction!

Cercidiphyllum (Siebold & Zucc.), commonly known as katsura, represents a small genus in the family Cercidiphyllaceae comprising approximately two species (C. japonicum and C. magnificum) native to East Asia. The genus exhibits a disjunct distribution across China, Japan, and Korea, occupying temperate mixed forests from lowland to mountainous regions. The type species, C. japonicum, was described by Siebold and Zuccarini in 1835.

Morphologically, Cercidiphyllum is distinguished by its small to medium-sized deciduous trees with opposite to subopposite leaves that emerge reddish before turning green, then brilliant yellow-orange in autumn. The leaves possess distinctive palmate venation with three primary veins and are held on petioles up to 4 cm long. The species is dioecious, bearing small, inconspicuous flowers in early spring before leaf emergence, with males producing dense clusters of pinkish stamens and females developing elongated styles. The ovary is superior with multiple carpels developing into small follicles containing flattened seeds with conspicuous wings.

The genus shows its highest diversity in Japan, where C. japonicum exhibits considerable morphological variation, while C. magnificum represents a larger, more robust form. China harbors scattered populations of C. japonicum with several recognized varieties. These trees typically inhabit moist, well-drained soils in valleys and along streams at elevations ranging from sea level to 2400 meters, often in association with Fagus and Quercus species.

Pollination occurs through wind dispersal of pollen, while seed dispersal appears limited, contributing to relatively local population establishment. Chromosome counts consistently report n=16 as the base number across the genus.

Recent molecular phylogenetic studies consistently place Cercidiphyllaceae within the order Saxifragales, near Hamamelidaceae, though exact relationships remain somewhat unresolved (Xiang et al., 2017; Soltis et al., 2011). Traditional sectional treatments based on C. japonicum varieties remain in use, though molecular data suggests these may not represent monophyletic lineages. Alternative taxonomic interpretations recognizing broader species concepts have been proposed, reflecting ongoing taxonomic debate.

The genus holds significant horticultural value, particularly C. japonicum as an ornamental tree prized for its fall foliage and elegant form. It serves as a valuable timber species in East Asia, valued for its light, fine-grained wood. While not widely naturalized elsewhere, it occasionally establishes in forest edges within its native range.

Conservation concerns focus on habitat fragmentation and climate change impacts on disjunct populations, particularly in China where forest degradation has reduced suitable habitats. The genus exemplifies the need for continued population monitoring and habitat protection to ensure long-term viability of this taxonomically and ecologically significant lineage.

Pick a Species to see its components: