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Near the eastern end of the long bridge are trees illus- 
trating the senna family, the pea family, the rue family, and 
the mahogany family. One of those in the senna family is 
the honey-locust or three-horned acacia (Gledits?a), a native 
of the southeastern United States ; its durability when in con- 
tact with the ground makes its wood of especial value for 
fence posts, for which purpose it is largely used; from China 
and Japan comes the Japanese locust, also represented here. 
One of the representatives of the pea family, from the Amur 
region, is the Amur yellow-wood (Maackia). Another is the 
locust-tree (/robinza), a native of the southeastern United 
States, but extensively naturalized elsewhere; its wood is 
hard and close-grained, and is very durable when in contact 
with ground or with water, so the high value in which it 
is held for fence posts and for ship-building may be readily 
understood. The rue family has for representatives the 
Japanese cork-tree (Phellodendron), from Japan, and the 
Chinese cork-tree, from the Amur region, China and Japan. 
The mahogany-tree family has a single species represented, 
the Chinese bastard-cedar, a native of China; the mahogany 
tree itself, and other representatives of the family, will be 
found at the conservatories. 
On the ridge to the northeast of the apple family, and to 
the west of the new conservatory site, are trees of the ailan- 
thus and sumac families. The former is represented by the 
Ailanthus, or tree-of-heaven, a native of China, but exten- 
sively naturalized in the eastern parts of the United States, 
where in some places it has become a nuisance, both on 
account of its ill-smelling staminate flowers and its habit of 
freely suckering from the roots. Among the sumacs (/thus) 
are Osbeck’s sumac, from China; the staghorn sumac, native 
of the eastern United States, from the young shoots of which 
the pipes for drawing off sap from sugar-maple trees are 
often made; the bark of its root is especially rich in tannin; 
the narrow-winged sumac is a representative from the Hima- 
layan region. 
On the ridge to the west of the new conservatory site, and 
