From epubbooks.com:
Allan and the Holy Flower is a 1915 novel by H. Rider Haggard featuring Allan Quatermain. It first appeared serialised in The Windsor Magazine. Brother John, who has been wandering in Africa for years, confides to Allan a huge and rare orchid, the largest ever found. Allan arrives to England with the flower and there he meets Mr. Somers, an orchid collector who is willing to finance an expedition to find the plant.