See Map: F, 1, 2, 23 
CORKTREE 
Phellodendron amurense 
Home to the corktree, the Amur River 
flows eastward from Mongolia as the 
eastern segment of the border between 
the Soviet Union and China. An exotic 
but accessible north temperate region, 
the Amur rewarded plant explorers in 
the last century with horticultural 
treasures. For instance, at the Missouri 
Botanical Garden you can also find the 
Amur cherry (Prunus maackii) and the 
Amur maackia (Maackia amurensis), both 
discovered in the Amur region by the 
plant explorer Maack. The discoverer of 
the corktree, in 1853, was Franz Josef 
Rupprecht, ei began life roaming with the Austrian Army in which his 
father was an officer during the Napoleonic Wars. Franz Josef trained as a 
physician but gave up that career at age 24 to explore for plants across 
what is now the Soviet Union. He became a prominent and influential 
Russian botanist. 
The corktree is among the few cool-climate members of the large, 
mostly tropical, Citrus Family (Rutaceae), which includes oranges, 
lemons, and grapefruits. The resemblance of the corktree to these familiar 
fruits may seem unconvincing, but the fragrance of its crushed fruits 
helps make the connection. (But please do not break off fruits at the 
Garden for a sniff.) The trees are strictly male or female, so only half of 
them bear fruits, which contain a natural insecticide. 
A small number of other members of the Citrus Family grow in 
Missouri. Native species are prickly-ash (Zanthoxylum americanum) and 
hoptree (Ptelea trifoliata). Introduced cultivated species are gas plant 
(Dictamnus albus), “hardy-orange” (Poncirus trifoliata), and rue (Ruta 
graveolens). Some of these are displayed at the Garden. 
With inconspicuous flowers and small fruits, the main attractions of 
the corktree are its deep green, compound leaves and massive, “low”, 
spreading main branches. Be sure to notice the shapes of the specimens 
northeast of the Climatron and next to the sculpture Victory. 
The name “corktree” reflects the resemblance of the bark of this 
species to that of the true cork (Quercus suber), which is an oak. Phello- 
dendron is Latin for “ cork-tree”, and amurense means “ Amur-dweller” . 
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