Kadua haupuensis (Rubiaceae: Spermacoceae), a new endemic species from Kaua’i, Hawaiian Islands
The new species Kadua haupuensis is described and illustrated from the isolated Mt. Ha’upu region of Kaua’i, Hawaiian Islands. This new species belongs to Kadua subg. Kadua sect. Wiegmannia. It is characterized by a subdioecious (leaky dioecious) breeding system and appears most closely related to another apparently dioecious species endemic to Kaua’i, Kadua flynnii, with which it is compared. Although the only original wild population is critically endangered and may possibly be extinct, this new species has been successfully propagated and is currently secure in cultivation.
Key WordsEndemic Kadua Kaua’i Hawaiian Islands Rubiaceae subdioecious
Our sincere thanks go to Kenneth R. Wood who made the original field collections and pointed out the distinctiveness of this species as well as providing the map, and Robert Nishek who carefully grew and tended the plants in the NTBG nursery. The assistance of the NTBG “Na Lima Kokua” volunteers in the experimental work of WGL, alluded to in this paper, is gratefully acknowledged. Stephen G. Weller provided insightful discussions of breeding systems. The illustration was skillfully drawn by Alice Tangerini of the Smithsonian Institution. We thank Rae Matthews and Mel Gabel for formatting the figures and Marjorie Knowles and Harold Robinson of the Smithsonian Institution for preparing the SEM seed images. Our reviewers Harold Robinson and Edward Terrell provided most helpful suggestions for improving the manuscript. The contribution by WLW to this study was partially supported by the Smithsonian Research Opportunities Fund and while appointed as McBryde Chair at the National Tropical Botanical Garden.
- Fosberg, F. R. 1943. The Polynesian species of Hedyotis (Rubiaceae). Bernice P. Bishop Museum Bulletin 174. 102 pp.Google Scholar
- Pailler, T., L. Humeau, J. Figier, & J. D. Thompson. 1998. Reproductive trait variation in the functionally dioecious and morphologically heterostylous island endemic Chassalia corallioides (Rubiaceae). Biological Journal of the Linnean Society 64: 297–313.Google Scholar
- Terrell, E. E. 1996. Revision of Houstonia (Rubiaceae—Hedyotideae). Systematic Botany Monographs 48: 1–118.Google Scholar
- Wagner, W. L., D. R. Herbst & S. H. Sohmer. 1990. Manual of the flowering plants of Hawai’i. University of Hawaii Press and Bishop Museum Press.Google Scholar
- Wood, K. R. 2005. Summary report of botanical research, Ha`upu Summit, Kaua’i, Hawai’i. Unpublished report, Aug. 2005, National Tropical Botanical Garden. 24 pp.Google Scholar