Pollen (microsporocyte, pollen mother cell or meiocyte), after meiotic division. After the formation of the four microspores, which are contained by callose walls, the development of the pollen grain walls begins. The callose wall is broken down by an enzyme called callase and the freed pollen grains grow in size and develop their characteristic shape and form a resistant outer wall called the exine and an inner wall called the intine. The exine is what is preserved in the fossil record. Two basic types of microsporogenesis are recognised, simultaneous and successive. In simultaneous microsporogenesis meiotic steps I and II are completed
What Is This Thing Called Love? What Is This Thing Called Love? "What Is This Thing Called Love?" is a 1929 popular song written by Cole Porter, for the musical "Wake Up and Dream". It was first performed by Elsie Carlisle in March 1929. The song has become a popular jazz standard and one of Porter's most often played compositions. "Wake Up and Dream" ran for 263 shows in London. The show was also noticed in New York, and the critics praised Tilly Losch's performance of the song. The show was produced on Broadway in December 1929; in the American rendition, "What Is This Thing Called