We present chemical images of Arabidopsis thaliana stem cross-sections acquired by confocal Raman microscopy. Using green light (532 nm) from a continuous wave laser, the spatial distributions of cell wall polymers in Arabidopsis are visualized for the first time with lateral resolution that is sub-gm. Our results facilitate the label-free in situ characterization and screening of cell wall composition in this plant biology and genetics model organism, contributing ultimately towards an understanding of the molecular biology of many plant traits. (C) 2010 Elsevier Inc. All rights reserved.