Guavas.

Guavas are common along the Highway, before the lush, lowland forests, the bushes line the roadside and are prolific off the beaten track. The bushes are rounded and the fruits circular and lemon sized, with knobbly skin and succulent pink flesh peppered with seeds. Pick all you want to eat on the island, but they are not allowed on the Mainland!  For more info on guava and other Hawaiian fruit, check in with Hana Picnic Co.