Each year, about 2,000 new plant species are being discovered, adding to the total number of ~391,000 species of vascular plants on our planet. Each plant is unique, with distinct lifespan and morphology. The diverse shapes of plants are generated through localized cell division and differential cell growth in meristematic tissues. Cell division and differentiation at the shoot apical meristem (SAM) lead to the formation of all above-ground plant organs. My research aims to understand how stem cells in the SAM grow and divide, and how developmental programs and environmental cues are integrated into stem cell maintenance and differentiation.