A synoptic revision of Olax L. (Olacaceae) in Madagascar and the Comoro Islands Zachary S. ROGERS Missouri Botanical Garden, P.O. Box 299, St. Louis, MO 63166-0299 (USA)
[email protected] Valéry MALÉCOT UMR A 462 SAGAH, Institut national d’Horticulture, 2 rue Le Nôtre, F-49045 Angers cedex 01 (France)
[email protected] Kendra G. SIKES Santa Monica Mountains National Recreation Area, 401 West Hillcrest Drive, Thousand Oaks, CA 91360-4223 (USA)
[email protected] Rogers Z. S., Malécot V. & Sikes K. G. 2006. — A synoptic revision of Olax L. (Olacaceae) in Madagascar and the Comoro Islands. Adansonia, sér. 3, 28 (1) : 71-100. ABSTRACT A synoptic revision of Olax L. from Madagascar and the Comoro Island Archi- pelago is provided based on morphological data gathered from a study of her- barium specimens. We recognize eight species of Olax occurring in this region, including three new species, O. antsiranensis, O. capuronii, and O. mayottensis. Olax antsiranensis has coriaceous leaves with an emarginate apex, a 5-petaled fl ower, and fruit with a weakly accrescent calyx. Olax capuronii has leaves of similar shape and size, but possesses a 3-petaled fl ower and a non-accrescent calyx in fruit. Olax mayottensis has larger acuminate leaves, 5 petals per fl ower, KEY WORDS and a fruit which is completely surrounded by an accrescent calyx. All of the Olacaceae, Olax, newly described species are of conservation concern because of their restricted Madagascar, ranges, with both O. capuronii and O. mayottensis considered endangered. Of Comoros, the eight species treated here, six species are endemic to Madagascar, O.