The venation pattern in atis (Annona squamosa) leaves is known as reticulate venation. In reticulate venation, the veins form a network-like structure with interconnected and branching patterns throughout the leaf blade. The primary veins, which are the main veins extending from the base of the leaf, divide and branch into secondary veins. The secondary veins further subdivide into tertiary veins and so on, creating a dense network of veins that facilitate the transport of water, nutrients, and photosynthetic products within the leaf tissue. This intricate venation pattern provides efficient support and maximizes the leaf's surface area for efficient sunlight absorption and gas exchange, which are crucial processes for photosynthesis and overall plant growth.