Rabindranath lived in the heyday of British India. He saw all the myriads of tropical seasonal and perennial flowers. He used to spend his summers in hills of Darjeeling and there he saw all the European flowers. Indians and Bangladeshis swoon to the lyrics of his flower songs.
This poem has got some Arabian flavor. The first line is totally Arabian, the name and the blessings to the tribe. Angels writing in book is also from Arab folklore. The poet may have been inspired by the book of Arabian Nights. With all the wars and killings going on in the Arab domains, it seems, they don't follow what is indicated in the poem.