Grevillea robusta. Proteaceae. Silk-Oak. Southern and Central
areas. Evergreen. Australia.
 Silk-oak is a tall (up to 100 feet), rapid-growing, evergreen tree
of upright habit. Leaves of this tree are feathery and silky in appear-
ance, being bipinnately compound with 11 to 21 pinnae; secondary
lobes are usually about an inch long, entire or again lobed (Fig. 31).
Leaves are 6 to 8 inches long and almost as broad, silky white on
lower surfaces and deep green above. Large, golden yellow or orange
colored racemes of flowers, up to 4 inches long, are borne in profusion
for several weeks, beginning usually in April and May.
 Silk-oak is especially well adapted to well-drained sandy soils of
central Florida and for coastal plantings. However, trees are subject
to wind damage and easily uprooted during hurricanes. Silk-oak is
useful as a street, roadside and specimen tree and in situations re-
quiring drought resistance. This tree is subject to mushroom root-
rot and infrequent attack by caterpillars.

 Guaiacum sanctum. Zygophyllaceae. Lignum Vitae or Holywood
 Lignumvitae. Southern area. Partially deciduous. Native.
 Lignum vitae, is a dense, oval-headed small tree that grows to


Fig. 31.-Leaf and flowers of the silk-oak, Grevillea robusta.