On the Cover: Leaf angle is an important agricultural trait determining leaf erectness and, hence, the photosynthesis efficiency and grain yield. Rice leaf angle is determined by lamina joint, and elucidation of the regulatory network of lamina joint development will contribute to molecular breeding of ideal architecture of rice. However, the understanding of morphological changes, cytological transitions, and underlying transcriptional programming is still limited. In this issue, studies by Zhou et al. (pp. 1728–1746) reveal a dynamic and a common–but distinct–development of lamina joint at successive stages accompanying sequential cell division and expansion of parenchyma cells, differentiation of sclerenchyma cells, cell wall thickening, and programmed cell death (PCD). The increased leaf angle results from the asymmetric cell proliferation and elongation at the adaxial or abaxial sides. Analysis of the transcriptome at four developmental stages ranging from initiation to senescence indicate that dynamic cytology is fine-regulated by multiple processes, including phytohormone signaling, transcription, and protein phosphorylation. Furthermore, phytohormones may regulate the lamina joint development synergistically and antagonistically. The image shows the rice lamina joint anatomies at stage 4, and the vascular bundles, sclerenchyma cells (newly formed), and parenchyma cells are highlighted with purple, green, or blue shade colors, respectively. Cover art by Li-Juan Zhou.