Ethnobotanical and floristical study of Alstonia boonei De Wild. (Apocynaceae) in the Makokou region, Ogoué- Ivindo province, Gabon

1 Department of Botany, Faculty of Sciences, University of Douala, Cameroon, BP 24 157 Douala. 2 Faculty of Sciences, University of Bangui, ,BP 908, Avenue des Martyrs, Bangui, Central African Republic. 3 INDEFOR, APDO 207, Bata, Equatorial Guinea. 4 Institut des Recherches en Ecologie Tropicale (IRET), Centre National de la Recherche Scientifique et Technologique (CENAREST), BP: 13 354 – Libreville, Gabon