Pacific Hibiscus (Malvaceae) in Sect. Lilibiscus. 1. Hibiscus kokio and Related Species From the Hawaiian Archipelago

The red-orange flowered clade of Hawaiian Hibiscus species in sect. Lilibiscus are discussed and a botanical key provided. Four species are recognised, viz. Hibiscus kokio Hillebr., H. clayi O. Deg. & I. Deg., H. kahilii C.N. Forbes, and H. saintjohnianus M. Roe. These species are uncommon or rare in nature, but vital elements in the diverse ecosystems in which they occur. Surprisingly, distinctive hibiscus species in this group are still being confused. An incomplete and contested understanding of the taxonomy of these species has hindered their conservation—both in situ and ex situ—and effective use in horticulture and landscaping. Recommendations are provided on conservation measures required to maintain and enhance genetic diversity within these four species, which are threatened by extreme weather events and climate change, invasive alien species, habitat loss, and land degradation.