Classification of Boraginaceae subfam. Ehretioideae: Resurrection of the genus Hilsenbergia Tausch ex Meisn. James S. MILLER Missouri Botanical Garden, P.O. Box 299, St. Louis, Missouri 63166-0299 U.S.A.
[email protected] ABSTRACT The genus Hilsenbergia (Boraginaceae: Ehretioideae) is resurrected to accom- modate a group of east African and west Indian Ocean species that have been included in Ehretia or Bourreria by other authors. These species differ from the pantropical Ehretia in having 4 winged to ridged pyrenes in the fruit, flowers with valvate calyx lobes, and fleshy, urceolate corollas. Hilsenbergia differs from the Neotropical Bourreria in having fruits that lack a fibrous connection between the apex of the pyrenes and the gynobase and having smaller flowers with urceolate corollas, as well as in its African/Indian Ocean distribution. As defined here, Hilsenbergia consists of 18 species, 13 of which KEY WORDS are endemic to Madagascar and all of these are newly described. A key and Hilsenbergia, nomenclatural notes for all species and full descriptions for the thirteen new Ehretia, species that are described are provided. Conservation analyses indicate that all Boraginaceae, Madagascar, of the Hilsenbergia species from Madagascar are threatened and five species Conservation. are critically endangered and nine are endangered. RÉSUMÉ Classification des Boraginaceae subfam. Ehretioideae : Réhabilitation du genre Hilsenbergia Tauch ex Meisn. Le genre Hilsenbergia (Boraginaceae : Ehretioideae) est réhabilité pour un groupe d’espèces d’Afrique orientale et de l’ouest de l’Océan Indien qui ont été placées dans Ehretia ou Bourreria par divers auteurs. Ces espèces diffèrent du genre pantropical Ehretia par les pyrènes du fruit ornées de 4 côtes ailées, et les fleurs à lobes du calice valvaires et une corolle charnue urcéolée.