‘Akala (Rubus hawaiensis) is the more common of the two endemic raspberries in Hawai‘i (the rarer species, R. macraei, is also known commonly as ‘akala), occurring as an understory shrub in mid to upper elevation mesic to wet forests. Rubus hawaiensis is known for its unusually large fruit and large leaves. The fruit is edible, although somewhat bitter, and has not been utilized for commercial production. The use of ‘akala in commercial breeding programs to increase fruit size has been considered, however.
A striking concentric, or spiraling ring pattern has been observed on leaves of R. hawaiensis, sometimes being limited to only a few leaves per plant, but sometimes affecting the majority of leaves. The pattern may be large enough to occupy most of the surface area of the leaf (up to about 8 cm in diameter), with many necrotic rings alternating with green tissue, or may be somewhat smaller, with only a few rings. The necrotic rings are evident on both leaf surfaces. Symptomatic leaves have been assayed for presence of viruses (R. Converse, unpublished) with negative results. Otherwise, nothing is known concerning the condition's cause.