MORPHOLOGY AND WOOD ANATOMY
Click on the thumbnail for a larger picture!
MORPHOLOGY
Tree form, flower position, seed shape and seed position in the pod vary greatly among populations of koa.
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| Big Island koa flowers, in axillary position | Kaua'i koa flowers, in axillary and terminal positions | Koai'a flowers, in terminal position |
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| Big Island Seedling: phyllodes are broad or slightly curved and there is a distinct yellow pubescence on the stems and phyllodes. | Kaua'i Seedling: phyllodes are narrow or distinctly curved; stems and true leaves have a distinct red color. | Koai'a Seedling: phyllodes are very narrow and slightly curved |
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| Big Island koa seed, oriented perpendicular to pod suture. | Kaua'i koa seed, orientation varies and seeds are round. | Koai'a seed, oriented parallel to pod suture. | O'ahu seed pod, oriented perpendicular to pod suture. |
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| Tall
koa with a spreading crown. Note the person in the foreground.
(Umikoa Ranch, Hawai'i.) |
Tall
koa with straight trunks.
(Laupahoehoe, Hawai'i) |
Small
stature koa with a spreading crown. Note the backpack in the foreground.
(Koai'a Tree Sanctuary, Hawai'i) |
Tall
koa with a large trunk.
(Laupahoehoe, Hawai'i) |
WOOD ANATOMY
(koai'a) (koa)
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| Koa and Koai'a anatomy varies in vessel number and size. |
As you can see, koai'a wood is much harder than koa wood!
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| Koai'a
(Pu'uwa'awa'a Ranch, Hawai'i) |
Koa
(Honomalino, Hawai'i) |
CURRENT WOOD ANATOMY RESEARCH
Recent wood anatomy sections using more advanced techniques indicate that crystals are prevalent in the parenchyma cells of A.koa as well as A.koaia.
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| Cross section of fresh koa wood | Cross secction of koa wood under polarized light |