A New, Dioecious Species of Hedyotis (Rubiaceae) from Kaua'i, Hawaiian Islands, and the Taxonomy of Kaua'i Hedyotis schlechtendahliana Resolved

Abstract

A new, cliff-dwelling species, Hedy- otis flynnii, is described from the Hawaiian island of Kaua'i. It is distinguished by its conspicuously reticulate leaf venation, reduced leaves, and green- ish yellow or sometimes white corollas. Based on morphological observations, it appears to be the first species in the genus known to have a dioecious breeding system. Hedyotis flynnii also expresses a strong corolla size dimorphism, with staminate flow- ers much larger than the pistillate. The taxonomy of the polymorphic species Hedyotis schlechtendah- liana also is reconsidered recognizing the north- western Kaua'i populations as Hedyotis schlechten- dahliana subsp. waimeae, characterized by stiffly chartaceous to coriaceous reticulate leaves, open inflorescences, and subulate bracts and calyx lobes. A distinctive, cliff-dwelling species of Hedyotis was first recognized as possibly a new species in Limahuli Valley by Tim Flynn and Moses Bergau in 1985. Additional collections from valleys along the Na Pali coast of Kaua'i, especially from Kala- lau, established that it represented a new species. We now have ample material to ascertain that these populations represent a new species in the complex Hedyotis sect. Wiegmannia (Meyen) Fosberg. We also provide new analysis of a vexing problem in the complicated variation pattern in the related Hedyotis schlechtendahliana subsp. schlechtendah- liana, treated as a very polymorphic variety in the most recent treatment by Wagner et al. (1990) and as four species by Fosberg (1943). We were able to clarify the taxonomy of this complex by study of numerous additional collections made during the past 10 years on Kaua'i, especially the northern half of the island. Our conclusion is that two mor-