The underground system known as the saxophone stem produced by seedlings of certain palm species exhibits unique growth patterns and distinctive morphologies. Nascimento e Souza et al. performed morpho-anatomical evaluations of seedlings during the development of the saxophone stem in Acrocomia aculeata, a neotropical oleaginous palm.
They found the development of the saxophone stem is distinct from other underground systems previously described, and involves three processes: growth and curvature of the cotyledonary petiole, expansion and curvature of the hypocotyl, and expansion of the plumule internodes. The saxophone stem structure represents an important adaptation to dry environments by promoting the burial of both the shoot apex and storage reserves, which facilitates the continuous growth of aerial organs.
E Souza, J. N., Ribeiro, L. M., & Mercadante-Simões, M. O. (2016). Ontogenesis and functions of saxophone stem in Acrocomia aculeata (Arecaceae). Annals of Botany, 119(3), 353–365. https://doi.org/10.1093/aob/mcw215