From Common Forest Trees of Hawaii

Āulu
Sapindus oahuensis
Maple family (Sapindaceae)

Native species ()

This medium-sized tree native to Oahu and Kauai is a relative of the widespread species wingleaf soapberry, Sapindus saponaria L., but differs in that the leaves are rather than A tree to 60 ft (18 ) high and 1 1⁄2 ft (0.5 ) in trunk diameter. Bark gray, smoothish, slightly fissured. Inner bark is light orange streaked. Twigs light brown, finely hairy when young, becoming hairless, with tiny cracks, with small dark brown pointed hairy side buds.


©2008 David Eickhoff
Leaves hairless, with long slender leaf-stalks 3⁄4–2 inches (2–5 ) long, flattened above and enlarged at brown base. Blades narrowly or oblong, 3–6 inches (7.5–15 ) long and 1 1⁄4–2 3⁄4 inches (4–7 ) wide, blunt at base and extending slightly down leaf-stalks, gradually narrowed to point at not on edges, slightly thickened and leathery. Upper surface slightly shiny dark green with fine slightly curved side veins and sides curved up from light yellow lower surface dull light green with raised light yellow

Flower clusters () and at base of uppermost leaves, 2–6 inches (5–15 ) long, much branched, the long wide-spreading branches dark brown, finely hairy. Flowers are very numerous, male and female, short-stalked, slightly bell-shaped, about 1⁄4 inch (6 ) wide, light greenish yellow. Male flowers with of five overlapping rounded light green hairy 1⁄8 inch (3 ) long, of five spreading greenish white hairy petals 3⁄16 inch (5 ) long, eight on rounded and tiny Female flowers have similar and eight minute sterile on a and with elliptical slightly 2–3- and 2–3-celled and dot

an elliptical (coccus), sometimes two, 3⁄4–1 inch (2–2.5 ) long, shiny and leathery. Seed single, elliptical, black, 1⁄4–3⁄4 inch (12–20 ) long, rough.

Wood light brown, hard.

The seeds were used in home remedies as a cathartic and were strung in leis. Like those of the common soapberry, they may be poisonous.

Fairly common, scattered in dry forests at 200–2000 ft (61–610 ) altitude.

Special areas
Wahiawa, Bishop Museum

Range
Oahu and Kauai only

Other common names
kaulu, Oahu soapberry. The name lonomea is used on Kauai.

The trees of Kauai, known by the Hawaiian name lonomea, have been treated also as a separate species, Sapindus lonomea St. John (1977b).

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

cm -- A centimeter which is about 0.4 inches.

A simple leaf blade is one that is not divided into separate leaflets.

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

stigma - The tip of a pistil that receives the pollen.

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

endemic -- when restricted to a certain country or area.

midrib -- The central and most prominent vein of a leaf or leaf-like thing.

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

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

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

Like the teeth on a saw, leaves and other surfaces can have toothed edges.

bristle -- A straight, stiff hair.

A panicle is a much-branched inflorescence. The bottom flowers in a panicle open first.

A pistil is the female structure of many flowers. It contains one or more carpels. Each carpel contins an ovary, style and stigma. The stigma receives the pollen which grows thru the style to reach the ovary.

An evergreen tree retains a large portion of its green leaves all year.

lobe -- Rounded parts of a leaf (or other organ). Lobes bulge out about 1/4 of the leaf diameter.

calyx -- the sepals of a flower, typically forming a whorl that encloses the petals and forms a protective layer around a flower in bud.

fruit -- any seed-bearing structure in flowering plants. It is formed from the ovary after flowering.

A leaf is compound when multiple leaflets are on the same stem.

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

corolla -- The name for all the petals of a flower taken together.

ovate -- Oval, egg-shaped, with a tapering point.

Usually green, sepals typically function as protection for the flower in bud, and often as support for the petals when in bloom.

The botanical term "berry" is different from common usage. Strawberries and raspberries are not berries. But a tomatoe is. A true berry is a fruit with the seeds immersed in the pulp.

An ovary is a part of the female reproductive organ of the flower. Above the ovary is the style and the stigma, which is where the pollen lands and germinates to grow down through the style to the ovary.