Marasmius koae to the substrate. The fruit body has no distinctive taste or odor. The thin-walled spores are somewhat fusoid (spindle-shaped) to elongated ellipsoidal in shape, smooth, hyaline (translucent), and measure 12–14.5 by 4–4.8 μm. The basidia (spore-bearing cells) are club-shaped, four-spored, and clamped, measuring 24–28 by 7–9 μm. The species is endemic to Hawaii, where it has been found growing in dense groups on the rotting wood of koa ("Acacia koa"). Collections have been made only in the Koa/Ohia Montane Wet Forest on Kauaʻi island. Marasmius koae Marasmius koae is a species of agaric fungus in the Marasmiaceae family. Newly described
Acacia koa a diameter of . Flowering may be seasonal or year round depending on the location. Fruit production occurs when a koa tree is between 5 and 30 years old. The fruit are legumes, also called pods, with a length of and a width of . Each pod contains an average of 12 seeds. The long, wide seeds are flattened ellipsoids and range from dark brown to black in color. The pods are mature and ready for propagation after turning from green to brown or black. Seeds are covered with a hard seed coat, and this allows them to remain dormant