Mycorrhizae are vital fungal associations essential for the survival of orchids in natural ecosystems, providing the necessary resources for seed germination and seedling establishment. Tropical epiphytic orchids occupy distinctive ecological niches within forest canopy systems where nutrient scarcity, periodic water stress, and intense solar radiation create extreme environmental pressures that fundamentally shape plant physiology and survival strategies. Unlike terrestrial orchids rooted in organic-rich soils, epiphytic species depend entirely upon mycorrhizal fungal associations for acquisition of essential nutrients including nitrogen and phosphorus, necessitating particularly intimate and efficient symbiotic relationships maintained throughout the plant's life cycle. This study investigates the process, extent, and pattern of mycorrhizal colonization and its relationship with total phenolic content in the aerial roots of three tropical epiphytic orchid species: Rhynchostylis retusa (L.) Blume, Dendrobium Sonia (Grex)- and Vanda yellow (hybrids). Anatomical characterization using Phase Contrast Microscopy revealed that fungal entry occurs through the velamen and exodermis passage cells, eventually forming hyphal coils known as pelotones within the cortical cells. Quantitative estimation of phenolics suggests a direct correlation between anatomical characteristics, the degree of fungal colonization, and total phenolic production. These findings highlight the role of phenolics as adaptive defence agents that regulate the symbiotic relationship and prevent fungal parasitism.