Koa acacia

Koa acacia
	Koa acacia ( Acacia koa )
Systematics
	Eurosiden I
Order :	Fabales (Fabales)
Family :	Legumes (Fabaceae)
Subfamily :	Mimosa family (Mimosoideae)
Genre :	Acacia
Type :	Koa acacia
Scientific name
	Acacia koa
	A.Gray

The koa acacia ( Acacia koa ) is a species of the legume family (Fabaceae). It is only found in the Hawaiian Islands and is the second most common species on some of them.

description

Branch with phyllodes

Phyllodium with pinnate leaf sections on a young specimen

Vegetative characteristics

The koa acacia grows as a fast-growing and evergreen tree that can reach heights of up to 25–35 meters or more. The trunk diameter can be up to 200 centimeters or a little more (3.6 meters). The rough, scaly and cracked bark is grayish-brown.

The leathery phyllodes, which are usually strongly curved like a sickle, are approximately elliptical with a length of 7.5 to 26 centimeters and a width of 0.5 to 2.5 centimeters. Young plants have double-pinnate leaves of different sizes at the tip of the smaller phyllodes.

Generative characteristics

The axillary or terminal, racemose to panicle arranged, spherical inflorescences are about 0.8-1 centimeters in size, and consist of many (up to 50) flowers. The inflorescence shafts are around 1 centimeter long.

The Koa acacia is dichogamous and protandric pre-male. The cream-colored and hermaphrodite, sessile flowers are 2 millimeters in diameter and are radially symmetrical with a double flower envelope . The small chalice is cup-shaped. The 5 petals are elongated. The tufted, protruding stamens are more than twice as long as the petals . The single, Upper permanent carpel is hairy, the stylus is long and above.

The flat, brownish and leathery-woody, rarely opening and bare legumes are 8 to 20 centimeters long and 0.8 to 2.5 centimeters wide, relatively straight to slightly curved and are constricted between the seeds. The flat, blackish 6 to 12 seeds are elliptical with a length of 0.6 to 1.2 centimeters and a thickness of 0.4 to 0.7 centimeters and flattened on one side.

Chromosome number

The number of chromosomes is 2n = 26 and 52.

Occurrence

The natural range of the koa acacia is in Hawaii . It includes the islands of Hawaii , Kauaʻi , Lānaʻi , Maui , Molokaʻi and Oʻahu .

Inflorescences

Trunk cross-section, the reddish color of the wood is clearly visible

use

The reddish-brown, dense wood was already used by the native Hawaiians to make spears, fishing lures and fishhooks for sharks, oars and musical instruments such as mouth bows . Ukuleles made from this wood are considered particularly valuable. It was also used in house building, where it is still used today. The flowers and leaves were used to make leis .

Systematics

The first description of Acacia koa was made in 1854 by the American botanist Asa Gray in C. Wilkes: United States Exploring Expedition , Volume 1, pp 480-481. A synonym for Acacia koa A.Gray is Racosperma koa (A.Gray) Pedley , others are Acacia kauaiensis Hillebr. , Acacia hawaiiensis (Rock.) O.Deg. & I.Deg. , Acacia coa Walp. , Acacia heterophylla Hook. & Arn. , as well as Acacia koa var. waianaeensis H.St.John , Acacia koa var. lanaiensis Rock , A. koa var. latifolia (Benth.) H.St.John u. a.

literature

EL Little; RG Skolmen: Common forest trees of Hawaii (native and introduced). USDA Forest Service, Agriculture Handbook No. 679, 1989, pp. 16, 128, 131 f u. a., online (PDF), from US Forest Service, accessed May 17, 2019.
CR Elevitch, KM Wilkinson, JB Friday: Acacia koa (koa) and Acacia koaia (koai'a). Species Profiles for Pacific Island Agroforestry, Ver. 3, 2006, online (PDF), accessed May 17, 2019.
JF Rock : The Arborescent Indigenous Legumes of Hawaii. Botanical Bulletin No. 5, 1919, pp. 20-26, Pl. I-VI, online at babel.hathitrust.org.

Web links

Commons : Koa Acacia ( Acacia koa ) - Collection of images, videos, and audio files

Acacia koa at Useful Tropical Plants.

Individual evidence

↑ ^a ^b ^c ^d ^e ^f ^g Acacia koa. In: Flora of the Hawaiian Islands. Smithsonian National Museum of Natural History, accessed August 19, 2015 .
↑ EL Little; RG Skolmen: Common forest trees of Hawaii. P. 16.
↑ PJ Baker, PG Scowcroft, JJ Ewel: Koa (Acacia koa) Ecology and Silviculture. USDA Forest Service, Pacific Southwest, General Technical Report PSW-GTR-211, 2009, p. 21, online (PDF), from US Forest Service, accessed May 17, 2019.
↑ How wood affects the sound of your ukulele. Ukuleleinsider.de, June 24, 2019, accessed June 14, 2020 .
↑ Acacia koa. In: Native Plants Hawai'i. www.nativeplants.hawaii.edu, accessed on August 22, 2015 .
^ Acacia koa in the Germplasm Resources Information Network (GRIN), USDA , ARS , National Genetic Resources Program. National Germplasm Resources Laboratory, Beltsville, Maryland. Retrieved August 25, 2013.
^ Acacia koa at Tropicos.org. Missouri Botanical Garden, St. Louis, accessed August 22, 2015.

[FotHI-1] ↑ ^a ^b ^c ^d ^e ^f ^g Acacia koa. In: Flora of the Hawaiian Islands. Smithsonian National Museum of Natural History, accessed August 19, 2015 .

[2] EL Little; RG Skolmen: Common forest trees of Hawaii. P. 16.

[3] PJ Baker, PG Scowcroft, JJ Ewel: Koa (Acacia koa) Ecology and Silviculture. USDA Forest Service, Pacific Southwest, General Technical Report PSW-GTR-211, 2009, p. 21, online (PDF), from US Forest Service, accessed May 17, 2019.

[4] How wood affects the sound of your ukulele. Ukuleleinsider.de, June 24, 2019, accessed June 14, 2020 .

[Native-5] Acacia koa. In: Native Plants Hawai'i. www.nativeplants.hawaii.edu, accessed on August 22, 2015 .

[GRIN-6] Acacia koa in the Germplasm Resources Information Network (GRIN), USDA , ARS , National Genetic Resources Program. National Germplasm Resources Laboratory, Beltsville, Maryland. Retrieved August 25, 2013.

[Tropicos-7] Acacia koa at Tropicos.org. Missouri Botanical Garden, St. Louis, accessed August 22, 2015.