A study is being made of the time of initiation and development of the flower bud in three classes of tulips. All floral organs are present in November. The flower bud is twice as large in the earliest (Mendel) class than in the latest (Darwin) class, but the cytological condition in the anthers and ovules is strikingly similar; pollen is in the late quartet to early microspore stage, ovules are very small primordia with no evidence of integuments or megaporocyte. Expansion of flower bud size is in proportion to earliness, pollen development is virtually parallel, and megagamentophyte development is slightly more rapid in the earliest class
