Olulu is an endangered Hawaiian endemic whose natural populations feel well below 100 plants towards the end of the last Century. Bradley Evans, Introductory Gardens Horticulturist, bought this plant from a cool vendor at the Philadelphia Flower Show three or four years ago. I saw the same plants, admired them, then, put off by the price walked away. Brad bought it and donated it to the Arboretum. We all do some of this but Brad is the King of donations.
Ululu is a tropical caudiciform member of the Campanulaceae (and an endemic), I like those technical references! It's a curious plant with the appearance of an inverted turnip with a tuft of leaves at the top. Gawky and graceless, but the flowers are nice. The popular press took a fleeting interest in this plant a few years back; I recall seeing, in several places, a picture botanists roped off on a cliff face over the ocean, inspecting plants in situ.
I remember seeing this plant on Maui in a cultivated garden of native plants, and thinking it looked a lot like Cissus tuberosa, that I had had for many years, but the deciduous Cissus was topped seasonally by twining vines while the Olulu sported a perennial rosette of semi-succulent leaves.