File talk:Plant cell showing primary and secondary wall by CarolineDahl.jpg

Okay, I just need to say that this image is wildly inaccurate. The plant cell wall is not several times the diameter of the cell itself. For example, sclerenchyma fibers have some of the thickest walls. The wikipedia file at http://en.wikipedia.org/wiki/File:Plant_cell_type_sclerenchyma_fibers.png shows some of these fibers in cross section.