From Common Forest Trees of Hawaii

Lemonscented Gum
Corymbia citriodora
Eucalyptus-Like family (Myrtaceae)

Post-Cook introduction

Easily recognized by the strong lemon odor of crushed foliage, this eucalypt grows better at lower altitude than most of the others introduced to Hawaii. A handsome large tree 80–160 ft (24–48 ) high, with straight trunk 2–4 ft (0.6–1.2 ) in diameter. or thin. Bark smooth, gray, peeling in thin or patches and becoming mottled, exposing whitish or faintly bluish inner layer with powdery surface, appearing dimpled; on large trunks dark gray. Twigs slender, slightly flattened, light green, brownish tinged.

Forest And Kim Starr
Leaves with yellowish flattened leaf-stalks of 1⁄2–3⁄4 inch (13–19 ). Blades narrowly lance-shaped, 4–8 inches (10–20 ) long and 3⁄8–1 inch (10–25 ) wide, long-pointed at and short-pointed at base, thin, green on both surfaces, slightly shiny, with many fine parallel straight side veins scarcely visible. Juvenile leaves for three or more pairs, then stalked, narrowly to broadly lance-shaped with wavy margins, 1 1⁄2–5 inches (4–13 ) long and 1⁄2–1 inch (13–25 ) wide, slightly bristly hairy, green above, purplish beneath.

Flower clusters () lateral and to 2 1⁄2 inches (6 ) long, branched. Flowers many, 3–5 together on equal stalks (), about 1⁄2 inch (13 ) across the many spreading white Buds are short-stalked, egg-shaped, about 1⁄2 inch (13 ) long and 5⁄16 inch (8 ) wide, lid short, half-round with short point.

Seed capsules egg-shaped or urn-shaped, narrowed into short neck, 1⁄2 inch (13 ) long and 5⁄16–3⁄8 inch (8–10 ) wide, brown with scattered raised dots, with wide sunken and enclosed valves, opening by three narrow lines. Seeds are few, irregularly elliptical, more than 1⁄8 inch (3 ) long, blackish, and also many smaller ones nonfunctional.

Wood light brown to gray brown, very heavy ( gr. 0.85), very hard, strong and very tough; moderately durable to durable; straight or wavy grain. Works easily for a wood of its density. It has been used in Hawaii for boat framing, sugar mill conveyor belt slats, and general heavy construction. Also used on a small in Hawaii, and more extensively in South Africa, for handle stock. Relatively stable for a eucalypt, very slow drying, but maintains its shape well in drying without collapse or serious checking.

In Australia, it is considered a first-class saw timber with a wide range of uses including general and heavy construction and tool handles.

In Hawaii, commonly seen planted in the lowlands. There is an avenue of these trees at the entrance to Ualakaa Park (Round Top) on Oahu. It is the principal tree bordering Wahiawa Reservoir. The Division of Forestry had planted 127,000 trees in the forest reserves by 1960. It was frequently used on the island of Hawaii to make boundaries of various land ownerships and fence lines within the reserves and long single rows of the tree can be seen running through the forest near Hilo. A large tree grows alongside H-1 Freeway in Moanalua Gardens.

Strong lemon odor from the essential oil citronellal is produced by crushing the foliage. Leaves when distilled yield this oil, which is used as perfume for soap. On a warm still day in Hawaii, the smell near the trees can be almost overpowering.

Special areas
Wahiawa, Tantalus, Pepeekeo

Height 98 ft (30.0 ), c.b.h. 16 ft (4.9 ), spread 90 ft (27.4 ). Kaumana Drive, Hilo, Hawaii (1968).

Northeastern Australia (Queensland), from coast to more than 200 miles (322 km) inland. Usually mixed with other eucalypts.

Often planted as an attractive ornamental in Australia, but the is too sparse for shelterbelts. Adapted to summer rainfall climate and very extensively planted worldwide in warm monsoon tropics.

Other common names
lemon-scented-gum, spotted-gum, lemon-scented irongum (Australia)

Eucalyptus citriodora Hook., Eucalyptus maculata Hook. var. citriodora (Hook.) Bailey

stamen -- the pollen-producing reproductive organ of a flower; The stamen consists of an anther supported by a filament.

An umbel is a collection of flowers on short stalks which spread from a common point, somewhat like umbrella ribs.

scale -- A very small leaf around a dormant bud. Also other things that might remind one of fish scales on the surface of ferns, stems and the like.

synonym -- In botany a synonym is a species name that at one time was thought to be the correct name for a plant but was later found to be incorrect and has been replaced by a new name.

cm -- A centimeter which is about 0.4 inches.

Irregular flowers, such as those of the violet or the pea, are often bilaterally symmeteric. These flowers typically have petals of unequal size or shape.

In an opposite leaf arrangement the leaves come in pairs with one leaf on each side of a stem.

mm -- millimeter. About 1/25th of an inch.

alternate -- leaves alternate along the main stem and are attached singly.

m -- A meter is about 10% larger than a yard.

terminal -- Located at the end (the tip or the apex).

The apex is the tip or the furthest point from the attachment.

In regular flowers all parts of the flower are similar in size and arrangement. Symeteric.

corymb -- a much-branched inflorescence with the lower flowers having long stems.

canopy -- The foliage of a tree; the crown. Also the upper layer of a forest.

disc flowers are those in the center of a sunflower or daisy. Not a ray flower.

sp. -- The abbreviation for "species". The plural is "spp". When used it sometimes means that the exact species is unknown. For example, "Aster sp" would mean some species within the Aster genus but the writer may not know exactly which species.