Abstract: The development process of the flower of Paphiopedilum armeniacum was observed . It is found that P. armeniacum developed inflorescence primordium in May , then sheath in June and July, and bracts in July and August . All
organs of the flower were formed in late August and September. After the formation of the flower , the flower organs kept on growing and developing quickly . One sterile stamen ( staminode ), two fertile stamens and the style were not integrated at the early stages of the flower development , but fused to form the gynostemium in the late phase . Because of the different relative growth rate, the relative position and morphology of these three organs were different in the late phase. In addition, several batches of P. armeniacum were introduced to Kunming and cultivated in a greenhouse from July to September, the rate of plants with flower bud had significant difference in different batches, which further verified it is a key period for P. armeniacum to form the flower organs from the late August to the early September .

Key words: Paphiopedilum armeniacum