Native range: China, Japan

Leaves:

• simple
• opposite on delicate-looking petioles
• produced on spurs along its twigs, which are short stems with closely spaced leaves
• cordate or rounded
• 2-4” long
• palmately veined
• crenate-serrate margin
• purplish tan when unfolding, then finally bluish-green

Flowers:

• dioecious
• tiny flowers (red on male trees and green on female trees) appear in spring before the foliage
• male flowers develop from spurs before the leaves emerge
• female develop as leaves are expanding
• no perianth
• 4 small bracts
• males 15-20 stamen
• female pistils w/ red stigma
• not showy

Fruit:

• pollinated flowers on female trees are followed by clusters of greenish oblong pods (to 3/4” long) with winged seeds
• pods are clustered in leaf axil
• fruits mature in autumn
• seeds released in autumn through winter and are distributed by wind

Other characteristics:

• deciduous tree 30-60 ft. (and up to 100 ft.)
• slender trunk divided near base into several upright branches
• yellow or red fall color
• bark deeply furrowed and peeling in long strips
• distinctive smell in fall (variously described as smelling of cinnamon, burnt sugar, caramel or ripe apples)

Relevant info:

• one of the largest hardwoods in Asia
• only remaining species of an ancient genus, which is found in the fossil record in North America and Europe dating back >65 million years
• remaining populations are endemic to E China
• poor self-regeneration has contributed to “endangered” status in China

Ecology & Adaptations:

• native to China and Japan
• understory tree in moist forests, forest margins, especially by streams (riparian corridors) on gentle slopes
• 600-2700 m elevation
• high rainfall and relatively low light
• shade tolerant:
  • leaf arrangement and horizontal orientation avoids self-shading along branches
  • able to photosynthesize at low light levels
• pollination:
  • adapted to wind-pollination
  • flowers are produced in early spring before leaves unfurl
  • other adaptations include small flowers, no perianth, no nectaries and taste-plentiful pollen
  • clustered pod-like fruits contain numerous small seeds easily dispersed by wind
• seed germination:
  • forest stand regeneration is sporadic
  • most germination succeeds on bare, especially disturbed soil (small seeds can’t penetrate litter layer), which often coincides with higher light in forest gaps
• vegetative reproduction:
  • re-sprouts following disturbance in dynamic environments (e.g., gap formation in forest canopy, flooding in riparian corridors)
  • this vegetative regeneration compensates for low seedling survival (small seeds have difficulty penetrating litter layer, so establish in bare substrate of alluvial flats but cannot often survive there due to flooding)
  • re-sprouting also occurs as the tree ages, resulting in trees that can be over 200 years old
• cold tolerance – tolerates sub-freezing temperatures (down to -40ºC) at high elevations by producing substances, such as flavonol glycosides and gallotannins, that decrease freezing point and prevent ice-formation in xylem cells that transport water
• herbivory defense – tannins in leaves and bark deter herbivores