H. Rider Haggard 
Allan And The Holy Flower 

As the title 'Allan and the Holy Flower' is a 1915 novel by H. Rider Haggard featuring Allan Quatermain. This book is representing the adventures of Allan Quatermain, great English hunter in the wilds of Africa. This story relates an expedition for a rare orchid, and the search for the kidnapped wife of one of Quatermain's friends. The lady was missing 20 years earlier. The orchid search takes them to a concealed dying civilization in which the flower is considered holy.