Fig. 9.2-2. Longitudinal section of spurge stem (Euphorbia). This section has three non-articulated laticifers. The one on the right appears to become narrow or blocked in two areas (arrows), but it is an undulating tube that has bent close to the edge of the section. Where it appears wide with a white lumen, the microtome knife has cut the front and back walls away completely. Where it appears narrow and solid red, the knife has left either the front or the back wall in the section. The middle laticifer appears to suddenly stop in the bottom part of the micrograph, but it probably has just turned, so the microtoming has simply cut away that part. The laticifer might really stop at this point, but if so, we would expect the end wall of the cell to be thin and well-defined like the side walls; the end that it displays here is thick and ill-defined, which looks like a glancing cut through a curved tube. To the left are a few splotches of red; that is where the microtome just barely caught a bit of wall material of another laticifer.