Cyanea is a large genus of Hawaiian lobelioids which have a variety of interesting and occasionally very odd morphologies. Some are smallish understory plants, while others grow into very tall palm-like trees. Many species of haha are extremely prickly - particularly the younger plants. Unfortunately, haha tend to be extremely sensitive to habitat disturbance, and they disappeared rapidly as alien species have invaded native Hawaiian habitats. Many of the species are extinct, and many others only exist as a handful of individuals or small colonies in very remote locations.

The small haha - floribunda and pilosa - are locally abundant in windward forests. They are insect pollinated, reproduce quickly, and can take advantage of protected sites out of reach of feral mammals. They may sprout from sheer walls, grow among mossy rocks or in tangled deadfall, and colonies of cyanea floribunda often line the interior walls of fissures and even tree molds below ground. Occasionally well-protected individuals may grow to be about six feet tall. The larger cyanea species are much rarer, and usually grow on the ground or in muddy sites. Many of the larger species would have once been bird pollinated by nectivorious birds like the 'o'o, mamo and i'iwi, including cyanea tritomantha whose large flowers only sprout from the interior of its tall adult leaf crown. Most of their bird pollenators are extinct or restricted in range, and i'iwi have moved into the forest canopy and lost their habit of feeding on haha as feral pigs and cattle destroyed the native forest understory.

Cyanea species on Hawai'i:
Windward - Pilosa, Floribunda, Platyphylla, Tritomantha, Shipmanii;
Windward Extinct: Copelandii, Giffardii;
Ka'u & Kona - Marksii, Hamatiflora, Stictophylla;
Kohala - All Extinct: Cylindrocalyx, Pycnocarpa;
(Degeneriana == Floribunda)