From Common Forest Trees of Hawaii

Pendant Senna
Senna pendula
Pea family (Fabaceae)

Post-Cook introduction

This introduced tree planted in lowlands, especially along roadsides, has large showy clusters of numerous bright yellow flowers in late summer and many long narrow flat dark brown pods that remain attached and become unattractive. Medium-sized tree 60 ft (18 ) high with straight trunk and axis 1 ft (0.3 ) in diameter and erect Bark gray or light brown, smoothish, becoming slightly fissured. Inner bark is light brown, gritty and tasteless. Twigs are greenish and minutely hairy when young, turning brown.

©2007 Forest And Kim Starr
Leaves even 9–13 inches (23–33 ) long, with slender grooved green and reddish tinged, finely hairy axis. 12–22 on short stalks of 1⁄8 inch (3 ), oblong, of uniform size, 1 1⁄4–3 inches (3–7.5 ) long and 1⁄2–7⁄8 inch (13–22 ) broad, rounded at both ends, with tiny tip, not thin, upper surface slightly shiny green and almost hairless, and lower surface gray green with sparse tiny hairs.

Flower clusters () are large, erect and 8–12 inches (20–30 ) or more in length and 5 inches (13 ) broad. Flowers are almost on straight yellow green finely hairy stalks of 1–1 1⁄4 inches (2.5–3 ). is composed of 5 concave pointed greenish yellow, finely hairy 5⁄16 inch (8 ) long; of five short-stalked spreading nearly equal bright yellow petals 5⁄8–3⁄4 inch (15–19 ) long; seven of different lengths and three smaller sterile and with pale green, minutely hairy one-celled and curved Flowering from July to October.

Pods, so numerous that they sometimes give an untidy appearance to the tree, are 6–10 inches (15–25 ) long, about 1⁄2 inch (13 ) broad, and 1⁄16 inch (1.5 ) thick, stiff and often slightly curved, splitting up sides into two parts. Seeds are many, beanlike, elliptical, 5⁄16 inch (8 ) long, shiny dark brown.

The sapwood is light brown and the heartwood dark brown. The wood is heavy ( gr. 0.75) and hard. It has a beautiful figure on flat-sawn faces imparted by prominent parenchyma tissue that is reminiscent of a pheasant’s tail, causing the wood frequently to be called “pheasant wood.” The wood, which is very susceptible to attack by dry-wood termites, is used for small turnery and carvings and is very popular. Elsewhere, it is employed for posts, fuel, construction, furniture, and similar purposes. Tannin has been extracted from the bark.

Only about 1500 trees have been planted in the Forest Reserves, almost all on Oahu. It is not commonly planted now as an ornamental because of the messy appearance of its pods. However, many old trees are still seen along roads and in old gardens. A prime example is a labeled tree near the ewa-makai gate of Iolani Palace grounds.

The species has been widely planted in Puerto Rico and the Virgin Islands in recent years for ornament, shade, and windbreaks. The trees form good windbreaks because they retain a deep closed They are propagated by seeds, grow very rapidly in full sunlight, and are suitable for fuel within a few years. However, they are very susceptible to attack by insects there.

The seeds, pods, and foliage are toxic to hogs and cause death quickly after being eaten. As hogs relish the poisonous leaves, farmers in Puerto Rico have suffered losses. Trees blown over or broken by storms increase the danger. Thus, swine and perhaps other livestock should be kept away from these trees.

Planted in lowlands, especially along roadsides in Hawaii and escaping. Introduced about 1865.

Special area

Native of East Indies, Malaysia, India, and Sri Lanka, spread by cultivation. First described from Siam (now Thailand), as the common and scientific names indicate. Widely planted in the West Indies and naturalized locally. Planted also in southern Florida, Central America, and northern South America.

Other common names
kassod-tree, kolomona; casia de Siam (Puerto Rico)

Cassia siamea Lam., Sciacassia siamea (Lam.) Britton

This species is known for its showy flowers in late summer after most legumes cease blooming. However, other species are generally more attractive.

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

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.

cm -- A centimeter which is about 0.4 inches.

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

style -- This is a long and thread-like structure that connects the stigma with the ovary. A flower may have a single style, or several of them.

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.

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.

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

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

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

leaflets -- Each little leaf-like thing in a compound leaf is a leaflet.

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.

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

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

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

pinnate -- A compound leaf with two rows of leaflets.

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.