We first analyzed the Compound Library visible morphological modifications during the MK-0683 149647-78-9 floral process, from the vegetative meristem to the senescent flower using three rose cultivars. two diploid roses, are among the few roses genotypes that were used in the numerous crossings and hybridizations to create the modern roses. For example contributed major traits, like recurrent flowering and components of the characteristic tea scent of modern roses flowering rose that contributed the climbing trait for some garden roses. These three cultivars were chosen because they have very different flowering habits. However, continuing flowering limits our ability to sample enough vegetative meristems for transcriptome analyses. Therefore, to collect sufficient number of meristems, we also chose non recurrent flowering roses, R. wichurana and R. x hybrida cv. Rose flowers are composed of four organ types arranged in whorls, from the outer to the inner sepals, petals, stamens and carpels. Flower development stages have been determined for model plants such as A. thaliana. However, these development stages cannot be directly applied to the rose flower development. In contrast to A. thaliana flowers that are composed of four concentric whorls, rose flowers are composed of one whorl of 5 sepals and multiple whorls of petals, of stamens and of carpels. Furthermore, the floral architecture of modern roses differs from that of wild-type roses. For instance, modern rose varieties exhibit double flower character of high number of petals and modified numbers of stamens and carpels, whereas wild-type roses have 5 petals. Scanning electron microscopy was used to image floral initiation in Rosa sp. Based on these imaging data, we divided the floral initiation process into three stages. After bud outgrowth, the vegetative meristem is dome-shaped and narrow with leaf primordia on its flanks. This structure is typical of a vegetative meristem as previously described. Rapidly, when the new stems have acquired three fully expanded leaves, the meristem enlarges, emerges and leaf primordia are now invisible. Then, the meristem becomes floral characterized by a flat, large and doming structure. Similar enlargement and doming of the meristem were observed during the floral initiation in other related Rosaceae. Five morphologically distinct developmental stages were easily distinguished under a dissecting microscope. The four types of floral organs continue developing and flowers start opening. Then the flower fully opens, and finally senesces. GO molecular function analysis showed that 38 sequences had putative transcription factor activity.