a Center of Excellence in Biomathematics,

Several biological features are presented by different types of trees. Two types of such trees are considered in this paper. the first type is trees with n external nodes that each internal node have at least two children, and are used in neuro-science and called neuronal dendritic trees. The second type is trees with n internal nodes and m external nodes. This type of trees represent the secondary structure of RNA sequences, and called RNA trees. In this paper, we present two new parallel algorithms for generation of these two biological trees. Both algorithms are adoptive and cost-optimal and generate the trees in B-order. Computations run in an SM SIMD model. Keywords: Neuronal Dendritic Trees, RNA Trees, Parallel Algorithm, B-order.