ABSTRAK
Di wilayah Halmahera Barat, khususnya di Desa Lako Akediri dan Bobanehena, terdapat suatu upacara adat yang bertujuan menyambut kedewasaan gadis yaitu upacara oke sou. Penelitian mengenai etnobotani upacara oke sou pada Desa Lako Akediri dan Bobanehena belum pernah dilakukan. Penelitian tersebut bertujuan untuk menjelaskan spesies-spesies tumbuhan yang digunakan dalam seluruh tahapan upacara oke sou di kedua desa, menjelaskan pengaruh perbedaan umur terhadap pengetahuan etnobotani masyarakat di kedua desa, dan memahami presepsi masyarakat di kedua desa terhadap konservasi tumbuhan yang digunakan dalam upacara oke sou. Penelitian awal dilakukan pada bulan Mei-Juni 2014, kemudian dilanjutkan pada bulan September--Desember 2014. Pengambilan data dilakukan menggunakan metode wawancara semi terstruktur dan participant observation. Dari hasil penelitian tersebut, terdata sebanyak 111 spesies tumbuhan dari 49 famili digunakan pada seluruh tahapan upacara oke sou, 86 spesies di Desa Lako Akediri dan 87 spesies di Desa Bobanehena. Pada kedua desa, pengetahuan etnobotani upacara oke sou kelompok umur >55 tahun lebih tinggi dibandingkan kelompok umur 13--35 tahun dan 35--55 tahun. Sebanyak 41% spesies tumbuhan yang digunakan berasal dari hasil budidaya, 31% merupakan tumbuhan ruderal, dan 28% spesies tumbuhan hidup secara liar.

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ABSTRACT
In the region of West Halmahera, particularly in the village of Lako Akediri and Bobanehena, there is a ceremony aimed to welcome maturity girl named oke sou ceremony. Research on ethnobotany oke sou ceremony at both villages has never been done. The study aims to describe the species of plants that used in all phases of the oke sou ceremony at both villages, to explain the effect of difference in age toward knowledge of ethnobotany oke sou ceremony at community in both villages, and to understand the perception people at both villages about conservation of used plant in oke sou ceremony. Preliminary study conducted during May to June 2014, then resumed in September to December 2014. Data collection using semi-structured interviews and participant observation. From the results, recorded as many as 111 species of plants from 49 families used in all stages of the oke sou ceremony, 86 species in the village of Lako Akediri and 87 species in the village Bobanehena. In both villages, knowledge of ethnobotany about oke sou ceremony in age group >55 years higher than the age group 13-35 years and 35-55 years. As many as 41% plant species used were obtained from the cultivation, 31% were ruderal plants, and 28% of the species were obtained in the wild.