Fig. 7.3-3. Transverse section of vascular bundle of ragweed (Ambrosia). The red band marked by the three arrows is part of a simple perforation plate, but rather than lying parallel to the plane of cutting, the plate is tilted upward and the microtome knife passed right through it cutting most of it away and leaving only this one piece. The six white dots (three are indicated by arrows) on the rim are pits. The curved inner edge of the red band is the edge of the perforation itself.