<p>The exploration and high-value utilization of sustainable biomass materials have attracted substantial interest. In this study, ornamental bamboo biomass with varying growth forms influenced by different environmental conditions was investigated. The tissue anatomy and cell wall topochemistry of the bamboo species were analyzed via a series of advanced microscopic techniques. In addition, the crystal structures of the feedstocks and their variations attributed to bending effects were elucidated. After conventional mild acid pretreatment, the bioconversion performance of the bamboo materials was evaluated. Straight bamboo samples exhibited higher vascular bundle density, increased lignin content predominantly distributed in the middle lamella, and a greater proportion of crystalline cellulose located within the secondary wall of both fibers and parenchyma cells. These topochemical and supramolecular variations substantially influenced the pretreatment and bioconversion performance of the bamboo species. This study provides novel insights into the utilization and application of various bamboo processing materials for the development of value-added products.</p>